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Anup Bhalla, Santa Clara US

Anup Bhalla, Santa Clara, CA US

Patent application numberDescriptionPublished
20080233748ETCH DEPTH DETERMINATION FOR SGT TECHNOLOGY - A method for determining the depth etch, a method of forming a shielded gate trench (SGT) structure and a semiconductor device wafer are disclosed. A material layer is formed over part of a substrate having a trench. The material fills the trench. A resist mask is placed over a test portion of the layer of material. The resist mask does not cover the trench. The layer of material is isotropically etched. An etch depth may be determined from a characteristic of etching of the material underneath the mask. Such a method may be used for forming SGT structures. The wafer may comprise a layer of material disposed on at least a portion of a surface of semiconductor wafer; a resist mask comprising an angle-shaped test portion disposed over a portion of the layer of material; and a ruler marking on the surface of the substrate proximate the test portion.09-25-2008
20080265312Enhancing Schottky breakdown voltage (BV) without affecting an integrated MOSFET-Schottky device layout - This invention discloses a semiconductor power device that includes an active cell area having a plurality of power transistor cells. Each of said power transistor cells has a planar Schottky diode that includes a Schottky junction barrier metal covering areas above gaps between separated body regions between two adjacent power transistor cells. The separated body regions further provide a function of adjusting a leakage current of said Schottky diode in each of said power transistor cells. Each of the planar Schottky diodes further includes a Shannon implant region disposed in a gap between the separated body regions of two adjacent power transistor cells for further adjusting a leakage current of said Schottky diode. Each of the power transistor cells further includes heavy body doped regions in the separated body regions next to source regions surrounding said Schottky diode forming a junction barrier Schottky (JBS) pocket region.10-30-2008
20080272371RESISTANCE-BASED ETCH DEPTH DETERMINATION FOR SGT TECHNOLOGY - A method for determining the depth etch, a method of forming a shielded gate trench (SGT) structure and a semiconductor device wafer are disclosed. A material layer is formed over part of a substrate having a trench. The material fills the trench. A resist mask is placed over a test portion of the material layer thereby defining a test structure that lies underneath the resist mask. The resist mask does not cover the trench. The material is isotropically etched and a signal related to a resistance change of the test structure is measured. A lateral undercut D11-06-2008
20080290367Layouts for multiple-stage ESD protection circuits for integrating with semiconductor power device - A semiconductor power device supported on a semiconductor substrate includes a plurality of transistor cells each having a source and a drain with a gate to control an electric current transmitted between the source and the drain. The semiconductor further includes a source metal connected to the source region, and a gate metal configured as a metal stripe surrounding a peripheral region of the substrate connected to a gate pad wherein the gate metal and the gate pad are separated from the source metal by a metal gap. The semiconductor power device further includes an ESD protection circuit includes a plurality of doped dielectric regions of opposite conductivity types constituting ESD diodes extending across the metal gap and connected between the gate metal and the source metal on the peripheral region of the substrate.11-27-2008
20080309382MOSFET for synchronous rectification - This invention discloses a new MOSFET device. The MOSFET device has an improved operation characteristic achieved by connecting a shunt FET of low impedance to the MOSFET device. The shunt FET is to shunt a transient current therethrough. The shunt FET is employed for preventing an inadvertent turning on of the MOSFET device. The inadvertent turning on of the MOSFET may occur when a large voltage transient occurs at the drain of the MOSFET device. By connecting the gate of the shunt FET to the drain of the MOSFET device, a low impedance path is provided at the right point of time during the circuit operation to shunt the current without requiring any external circuitry.12-18-2008
20090008758USE OF DISCRETE CONDUCTIVE LAYER IN SEMICONDUCTOR DEVICE TO RE-ROUTE BONDING WIRES FOR SEMICONDUCTOR DEVICE PACKAGE - A semiconductor package assembly may include a lead frame having a die bonding pad and plurality of leads coupled to the first die bonding pad. A vertical semiconductor device may be bonded to the die bonding pad. The device may have a conductive pad electrically connected to one lead through a first bond wire. An electrically isolated conductive trace may be formed from a layer of conductive material of the first semiconductor device. The conductive trace provides an electrically conductive path between the first bond wire and a second bond wire. The conductive path may either pass underneath a third bond wire thereby avoiding the third bond wire crossing another bond wire, or the conductive path may result in a reduced length for the first and second bond wires that is less than a predetermined maximum length.01-08-2009
20090014853Integrated circuit package for semiconductior devices with improved electric resistance and inductance - A semiconductor integrated circuit package having a leadframe (01-15-2009
20090039456Structures and methods for forming Schottky diodes on a P-substrate or a bottom anode Schottky diode - This invention discloses bottom-anode Schottky (BAS) device supported on a semiconductor substrate having a bottom surface functioning as an anode electrode with an epitaxial layer has a same doped conductivity as said anode electrode overlying the anode electrode. The BAS device further includes an Schottky contact metal disposed in a plurality of trenches and covering a top surface of the semiconductor substrate between the trenches. The BAS device further includes a plurality of doped JBS regions disposed on sidewalls and below a bottom surface of the trenches doped with an opposite conductivity type from the anode electrode constituting a junction barrier Schottky (JBS) with the epitaxial layer disposed between the plurality of doped JBS regions. The BAS device further includes an ultra-shallow Shannon implant layer disposed immediate below the Schottky contact metal in the epitaxial layer between the plurality of doped JBS regions.02-12-2009
20090057869CO-PACKAGED HIGH-SIDE AND LOW-SIDE NMOSFETS FOR EFFICIENT DC-DC POWER CONVERSION - A circuit package assembly is disclosed. The assembly includes a conductive substrate; a high-side n-channel metal oxide semiconductor field effect transistor (NMOSFET) having a source on a side facing a surface of the conductive substrate and in electrical contact therewith and a low-side standard n-channel metal oxide semiconductor field effect transistor (NMOSFET) having a drain on a side facing the conductive substrate and in electrical contact therewith. Co-packaging of high-side and low-side NMOSFETs in this manner may reduce package size and parasitic inductance and capacitance compared to conventional packaging.03-05-2009
20090065814MOS device with schottky barrier controlling layer - A semiconductor device is formed on a semiconductor substrate. The semiconductor device comprises a drain, an epitaxial layer overlaying the drain, and an active region. The active region comprises a body disposed in the epitaxial layer, having a body top surface, a source embedded in the body, extending from the body top surface into the body, a gate trench extending into the epitaxial layer, a gate disposed in the gate trench, an active region contact trench extending through the source and the body into the drain, an active region contact electrode disposed within the active region contact trench, wherein the active region contact electrode and the drain form a Schottky diode, and a Schottky barrier controlling layer disposed in the epitaxial layer adjacent to the active region contact trench.03-12-2009
20090065855MOS device with integrated schottky diode in active region contact trench - A semiconductor device is formed on a semiconductor substrate. The device comprises a drain, an epitaxial layer overlaying the drain, and an active region. The active region comprises a body disposed in the epitaxial layer, having a body top surface and a body bottom surface, a source embedded in the body, extending from the body top surface into the body, a gate trench extending into the epitaxial layer, a gate disposed in the gate trench, an active region contact trench extending through the source and at least part of the body into the drain, wherein the active region contact trench is shallower than the body bottom surface, and an active region contact electrode disposed within the active region contact trench.03-12-2009
20090065861MOS device with low injection diode - A semiconductor device is formed on a semiconductor substrate. The device includes a drain, an epitaxial layer overlaying the drain, and an active region. The active region includes a body disposed in the epitaxial layer, having a body top surface, a source embedded in the body, extending from the body top surface into the body, a gate trench extending into the epitaxial layer, a gate disposed in the gate trench, an active region contact trench extending through the source and into the body, an active region contact electrode disposed within the active region contact trench, wherein a thin layer of body region separating the active region contact electrode from the drain.03-12-2009
20090072301Shielded gate trench (SGT) MOSFET cells implemented with a schottky source contact - This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one active cell further includes a trenched source contact opened between the trenches wherein the trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of the trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. A shielding structure is disposed at the bottom and insulated from the trenched gate to provide shielding effect for both the trenched gate and the Schottky diode.03-19-2009
20090108456Solder-top Enhanced Semiconductor Device and Method for Low Parasitic Impedance Packaging - A solder-top enhanced semiconductor device is proposed for packaging. The solder-top device includes a device die with a top metal layer patterned into contact zones and contact enhancement zones. At least one contact zone is electrically connected to at least one contact enhancement zone. Atop each contact enhancement zone is a solder layer for an increased composite thickness thus lowered parasitic impedance. Where the top metal material can not form a uniform good electrical bond with the solder material, the device die further includes an intermediary layer sandwiched between and forming a uniform electrical bond with the top metal layer and the solder layer. A method for making the solder-top device includes: 04-30-2009
20090127593MOS device - A semiconductor device includes a drain, an epitaxial layer overlaying the drain, a body disposed in the epitaxial layer, a source embedded in the body, a gate trench extending into the epitaxial layer, a gate disposed in the gate trench, an active region contact trench extending through the source, the active region contact trench having a varying contact trench depth, and an active region contact electrode disposed within the active region contact trench.05-21-2009
20090128223Thermally stable semiconductor power device - A semiconductor power device includes a circuit to provide a gate signal wherein the gate signal has a negative temperature coefficient of gate driving voltage for decreasing a gate driving voltage with an increase temperature whereby the semiconductor power device has a net Ids temperature coefficient that is less than or equal to zero. In an exemplary embodiment, the gate voltage driver includes a diode that has a negative forward voltage temperature coefficient connected between a gate and a source of the semiconductor power device. In another embodiment, the gate voltage is integrated with the semiconductor power device manufactured as part of an integrated circuit with the semiconductor power device.05-21-2009
20090166621RESISTANCE-BASED ETCH DEPTH DETERMINATION FOR SGT TECHNOLOGY - A method for determining the depth etch, a method of forming a shielded gate trench (SGT) structure and a semiconductor device wafer are disclosed. A material layer is formed over part of a substrate having a trench. The material fills the trench. A resist mask is placed over a test portion of the material layer thereby defining a test structure that lies underneath the resist mask. The resist mask does not cover the trench. The material is isotropically etched and a signal related to a resistance change of the test structure is measured. A lateral undercut D07-02-2009
20090166740Reduced mask configuration for power mosfets with electrostatic discharge (ESD) circuit protection - A semiconductor power device supported on a semiconductor substrate includes an electrostatic discharge (ESD) protection circuit disposed on a first portion of patterned ESD polysilicon layer on top of the semiconductor substrate. The semiconductor power device further includes a second portion of the patterned ESD polysilicon layer constituting a body implant ion block layer for blocking implanting body ions to enter into the semiconductor substrate below the body implant ion block layer. In an exemplary embodiment, the electrostatic discharge (ESD) polysilicon layer on top of the semiconductor substrate further covering a scribe line on an edge of the semiconductor device whereby a passivation layer is no longer required manufacturing the semiconductor device for reducing a mask required for patterning the passivation layer.07-02-2009
20090218619Self-aligned slotted accumulation-mode field effect transistor (AccuFET) structure and method - This invention discloses a semiconductor power device disposed in a semiconductor substrate. The semiconductor power device includes trenched gates each having a stick-up gate segment extended above a top surface of the semiconductor substrate surrounded by sidewall spacers. The semiconductor power device further includes slots opened aligned with the sidewall spacers substantially parallel to the trenched gates. The stick-up gate segment further includes a cap composed of an insulation material surrounded by the sidewall spacers. A layer of barrier metal covers a top surface of the cap and over the sidewall spacers and extends above a top surface of the slots. The slots are filled with a gate material same as the gate segment for functioning as additional gate electrodes for providing a depletion layer extends toward the trenched gates whereby a drift region between the slots and the trenched gate is fully depleted at a gate-to-drain voltage Vgs=0 volt.09-03-2009
20090218620High power and high temperature semiconductor power devices protected by non-uniform ballasted sources - This invention discloses a semiconductor power device disposed on a semiconductor substrate supporting an epitaxial layer as a drift region composed of an epitaxial layer. The semiconductor power device further includes a super-junction structure includes a plurality of doped sidewall columns disposed in a multiple of epitaxial layers. The epitaxial layer have a plurality of trenches opened and filled with the multiple epitaxial layer therein with the doped columns disposed along sidewalls of the trenches disposed in the multiple of epitaxial layers.09-03-2009
20090218890Robust semiconductor power devices with design to protect transistor cells with slower switching speed - This invention discloses a power switch that includes a fast-switch semiconductor power device and a slow-switch semiconductor power device controllable to turn on and off a current transmitting therethrough. The slow-switch semiconductor power device further includes a ballasting resistor for increasing a device robustness of the slow switch semiconductor power device. In an exemplary embodiment, the fast-switch semiconductor power device includes a fast switch metal oxide semiconductor field effect transistor (MOSFET) and the slow-switch semiconductor power device includes a slow switch MOSFET wherein the slow switch MOSFET further includes a source ballasting resistor.09-03-2009
20090219044Calibration technique for measuring gate resistance of power MOS gate device at wafer level - This invention discloses a method for calibrating a gate resistance measurement of a semiconductor power device that includes a step of forming a RC network on a test area on a semiconductor wafer adjacent to a plurality of semiconductor power chips and measuring a resistance and a capacitance of the RC network to prepare for carrying out a wafer-level measurement calibration of the semiconductor power device. The method further includes a step of connecting a probe card to a set of contact pads on the semiconductor wafer for carrying out the wafer-level measurement calibration followed by performing a gate resistance Rg measurement for the semiconductor power chips.09-03-2009
20090242973SOURCE AND BODY CONTACT STRUCTURE FOR TRENCH-DMOS DEVICES USING POLYSILICON - A semiconductor device includes a gate electrode, a top source region disposed next to the gate electrode, a drain region disposed below the bottom of the gate electrode, a oxide disposed on top of the source region and the gate electrode, and a doped polysilicon spacer disposed along a sidewall of the source region and a sidewall of the oxide. Methods for manufacturing such device are also disclosed.10-01-2009
20090250770INTEGRATION OF A SENSE FET INTO A DISCRETE POWER MOSFET - A semiconductor device includes a main field effect transistor (FET) and one or more sense FETs, and a common gate pad. The main FET and the one or more sense FETs are formed in a common substrate. The main FET and each of the sense FETs include a source terminal, a gate terminal and a drain terminal. The common gate pad connects the gate terminals of the main FET and the one or more sense FETs. An electrical isolation is disposed between the gate terminals of the main FET and the one or more sense FETs. Embodiments of this invention may be applied to both N-channel and P-channel MOSFET devices.10-08-2009
20090321929Standing chip scale package - A standing chip scale package is disclosed. The standing chip scale package provides electrical connection to bumped device contacts on both sides of the chip. The package is coupleable to a printed circuit board in a standing configuration such that front and back sides of the bumped chip are substantially perpendicular to a mounting surface. A process of fabricating the standing chip scale package is also disclosed.12-31-2009
20100024213COPPER BONDING METHOD - A copper bonding compatible bond pad structure and associated method is disclosed. The device bond pad structure includes a buffering structure formed of regions of interconnect metal and regions of non-conductive passivation material, the buffering structure providing buffering of underlying layers and structures of the device.02-04-2010
20100090276Shielded gate trench (SGT) MOSFET devices and manufacturing processes - This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one of the cells constituting an active cell has a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding the cell. The trenched gate further has a bottom-shielding electrode filled with a gate material disposed below and insulated from the trenched gate. At least one of the cells constituting a source-contacting cell surrounded by the trench with a portion functioning as a source connecting trench is filled with the gate material for electrically connecting between the bottom-shielding electrode and a source metal disposed directly on top of the source connecting trench. The semiconductor power device further includes an insulation protective layer disposed on top of the semiconductor power device having a plurality of source openings on top of the source region and the source connecting trench provided for electrically connecting to the source metal and at least a gate opening provided for electrically connecting the gate pad to the trenched gate.04-15-2010
20100105182Shallow source MOSFET - Fabricating a semiconductor device includes forming a hard mask on a substrate having a top substrate surface, forming a trench in the substrate through the hard mask, depositing gate material in the trench, where the amount of gate material deposited in the trench extends beyond the top substrate surface, and removing the hard mask to leave a gate having a gate top surface that extends substantially above the top substrate surface at least in center region of the trench opening, the gate having a vertical edge that includes an extended portion, the extended portion extending above the trench opening and being substantially aligned with the trench wall. It further includes implanting a body, implanting a plurality of source regions embedded in the body, forming a plurality of spacers that insulate the source regions from the gate, the plurality of spacers being situated immediately adjacent to the gate and immediately adjacent to respective ones of the plurality of source regions, wherein the plurality of spacers do not substantially extend into the trench and do not substantially extend over the trench, disposing a dielectric layer over the source, the spacers, the gate, and at least a portion of the body, forming a contact opening, and disposing metal to form a contact with the body at the contact opening.04-29-2010
20100148246Power mosfet device structure for high frequency applications - This invention discloses a new switching device supported on a semiconductor that includes a drain disposed on a first surface and a source region disposed near a second surface of said semiconductor opposite the first surface. The switching device further includes an insulated gate electrode disposed on top of the second surface for controlling a source to drain current. The switching device further includes a source electrode interposed into the insulated gate electrode for substantially preventing a coupling of an electrical field between the gate electrode and an epitaxial region underneath the insulated gate electrode. The source electrode further covers and extends over the insulated gate for covering an area on the second surface of the semiconductor to contact the source region. The semiconductor substrate further includes an epitaxial layer disposed above and having a different dopant concentration than the drain region. The insulated gate electrode further includes an insulation layer for insulating the gate electrode from the source electrode wherein the insulation layer having a thickness depending on a Vgsmax rating of the vertical power device.06-17-2010
20100155876Junction barrier Schottky (JBS) with floating islands - A Schottky diode includes a Schottky barrier and a plurality of dopant regions disposed near the Schottky barrier as floating islands to function as PN junctions for preventing a leakage current generated from a reverse voltage. At least a trench opened in a semiconductor substrate with a Schottky barrier material disposed therein constitutes the Schottky barrier. The Schottky barrier material may also be disposed on sidewalls of the trench for constituting the Schottky barrier. The trench may be filled with the Schottky barrier material composed of Ti/TiN or a tungsten metal disposed therein for constituting the Schottky barrier. The trench is opened in a N-type semiconductor substrate and the dopant regions includes P-doped regions disposed under the trench constitute the floating islands. The P-doped floating islands may be formed as vertical arrays under the bottom of the trench.06-24-2010
20100163846Nano-tube mosfet technology and devices - This invention discloses a semiconductor power device disposed in a semiconductor substrate and the semiconductor substrate has a plurality of trenches. Each of the trenches is filled with a plurality of epitaxial layers of alternating conductivity types constituting nano tubes functioning as conducting channels stacked as layers extending along a sidewall direction with a “Gap Filler” layer filling a merging-gap between the nano tubes disposed substantially at a center of each of the trenches. The “Gap Filler” layer can be very lightly doped Silicon or grown and deposited dielectric layer. In an exemplary embodiment, the plurality of trenches are separated by pillar columns each having a width approximately half to one-third of a width of the trenches.07-01-2010
20100190307HIGH DENSITY TRENCH MOSFET WITH SINGLE MASK PRE-DEFINED GATE AND CONTACT TRENCHES - Trench gate MOSFET devices may be formed using a single mask to define gate trenches and body contact trenches. A hard mask is formed on a surface of a semiconductor substrate. A trench mask is applied on the hard mask to predefine a body contact trench and a gate trench. These predefined trenches are simultaneously etched into the substrate to a first predetermined depth. A gate trench mask is next applied on top of the hard mask. The gate trench mask covers the body contact trenches and has openings at the gate trenches that are wider than those trenches. The gate trench, but not the body contact trench, is etched to a second predetermined depth. Conductive material of a first kind may fill the gate trench to form a gate. Conductive material of a second kind may fill the body contact trench to form a body contact.07-29-2010
20100200920Configuration of gate to drain (GD) clamp and ESD protection circuit for power device breakdown protection - A semiconductor power device supported on a semiconductor substrate comprising a plurality of transistor cells each having a source and a drain with a gate to control an electric current transmitted between the source and the drain. The semiconductor further includes a gate-to-drain (GD) clamp termination connected in series between the gate and the drain further includes a plurality of back-to-back polysilicon diodes connected in series to a silicon diode includes parallel doped columns in the semiconductor substrate wherein the parallel doped columns having a predefined gap. The doped columns further include a U-shaped bend column connect together the ends of parallel doped columns with a deep doped well disposed below and engulfing the U-shaped bend.08-12-2010
20100244090TVS with low capacitance & Forward voltage drop with depleted SCR as steering diode - A transient-voltage suppressing (TVS) device disposed on a semiconductor substrate of a first conductivity type. The TVS includes a buried dopant region of a second conductivity type disposed and encompassed in an epitaxial layer of the first conductivity type wherein the buried dopant region extends laterally and has an extended bottom junction area interfacing with the underlying portion of the epitaxial layer thus constituting a Zener diode for the TVS device. The TVS device further includes a region above the buried dopant region further comprising a top dopant layer of a second conductivity type and a top contact region of a second conductivity type which act in combination with the epitaxial layer and the buried dopant region to form a plurality of interfacing PN junctions constituting a SCR acting as a steering diode to function with the Zener diode for suppressing a transient voltage.09-30-2010
20100258897Trench junction barrier controlled Schottky - A method for manufacturing a Schottky diode comprising steps of 1) providing a region with a dopant of a second conductivity type opposite to a first conductivity type to form a top doped region in a semiconductor substrate of said first conductivity type; 2) providing a trench through the top doped region to a predetermined depth and providing a dopant of the second conductivity type to form a bottom dopant region of the second conductivity type; and 3) lining a Schottky barrier metal layer on a sidewall of the trench at least extending from a bottom of the top doped region to a top of the bottom doped region.10-14-2010
20100276779Transient Voltage Suppressor Having Symmetrical Breakdown Voltages - A vertical transient voltage suppressing (TVS) device includes a semiconductor substrate of a first conductivity type where the substrate is heavily doped, an epitaxial layer of the first conductivity type formed on the substrate where the epitaxial layer has a first thickness, and a base region of a second conductivity type formed in the epitaxial layer where the base region is positioned in a middle region of the epitaxial layer. The base region and the epitaxial layer provide a substantially symmetrical vertical doping profile on both sides of the base region. In one embodiment, the base region is formed by high energy implantation. In another embodiment, the base region is formed as a buried layer. The doping concentrations of the epitaxial layer and the base region are selected to configure the TVS device as a punchthrough diode based TVS or an avalanche mode TVS.11-04-2010
20100291744HIGH DENSITY TRENCH MOSFET WITH SINGLE MASK PRE-DEFINED GATE AND CONTACT TRENCHES - Trench gate MOSFET devices may be formed using a single mask to define gate trenches and body contact trenches. A hard mask is formed on a surface of a semiconductor substrate. A trench mask is applied on the hard mask to predefine a body contact trench and a gate trench. These predefined trenches are simultaneously etched into the substrate to a first predetermined depth. A gate trench mask is next applied on top of the hard mask. The gate trench mask covers the body contact trenches and has openings at the gate trenches. The gate trench, but not the body contact trench, is etched to a second predetermined depth. Conductive material of a first kind may fill the gate trench to form a gate. Conductive material of a second kind may fill the body contact trench to form a body contact.11-18-2010
20100314659Nanotube Semiconductor Devices - A semiconductor device includes a first semiconductor layer and a second semiconductor layer of opposite conductivity type, a first epitaxial layer of the first conductivity type formed on sidewalls of the trenches, and a second epitaxial layer of the second conductivity type formed on the first epitaxial layer where the second epitaxial layer is electrically connected to the second semiconductor layer. The first epitaxial layer and the second epitaxial layer form parallel doped regions along the sidewalls of the trenches, each having uniform doping concentration. The second epitaxial layer has a first thickness and a first doping concentration and the first epitaxial layer and a mesa of the first semiconductor layer together having a second thickness and a second average doping concentration where the first and second thicknesses and the first doping concentration and second average doping concentrations are selected to achieve charge balance in operation.12-16-2010
20100314682Configurations and methods for manufacturing devices with trench-oxide-nano-tube super-junctions - This invention discloses semiconductor power device disposed on a semiconductor substrate of a first conductivity type. The semiconductor substrate supports an epitaxial layer of a second conductivity type thereon wherein the semiconductor power device is supported on a super-junction structure. The super-junction structure comprises a plurality of trenches opened from a top surface in the epitaxial layer; wherein each of the trenches having trench sidewalls covered with a first epitaxial layer of the first conductivity type to counter charge the epitaxial layer of the second conductivity type. A second epitaxial layer may be grown over the first epitaxial layer. Each of the trenches is filled with a non-doped dielectric material in a remaining trench gap space. Each of the trench sidewalls is opened with a tilted angle to form converging U-shaped trenches.12-16-2010
20100314693INTEGRATION OF A SENSE FET INTO A DISCRETE POWER MOSFET - A semiconductor device includes a main field effect transistor (FET) and one or more sense FETs, and a common gate pad. The main FET and the one or more sense FETs are formed in a common substrate. The main FET and each of the sense FETs include a source terminal, a gate terminal and a drain terminal. The common gate pad connects the gate terminals of the main FET and the one or more sense FETs. An electrical isolation is disposed between the gate terminals of the main FET and the one or more sense FETs. Embodiments of this invention may be applied to both N-channel and P-channel MOSFET devices.12-16-2010
20100317158Method for Forming Nanotube Semiconductor Devices - A method for forming a semiconductor device includes forming a nanotube region using a thin epitaxial layer formed on the sidewall of a trench in the semiconductor body. The thin epitaxial layer has uniform doping concentration. In another embodiment, a first thin epitaxial layer of the same conductivity type as the semiconductor body is formed on the sidewall of a trench in the semiconductor body and a second thin epitaxial layer of the opposite conductivity type is formed on the first epitaxial layer. The first and second epitaxial layers have uniform doping concentration. The thickness and doping concentrations of the first and second epitaxial layers and the semiconductor body are selected to achieve charge balance. In one embodiment, the semiconductor body is a lightly doped P-type substrate. A vertical trench MOSFET, an IGBT, a Schottky diode and a P-N junction diode can be formed using the same N-Epi/P-Epi nanotube structure.12-16-2010
20100320461INTEGRATION OF SENSE FET INTO DISCRETE POWER MOSFET - A semiconductor device includes a main field effect transistor (FET) and one or more sense FETs. A transistor portion of the sense FET is surrounded by transistors of the main FET. An electrical isolation structure that surrounds the main FET is configured to electrically isolate source and body regions of the main FET from source and body regions of the sense FET. A sense FET source pad is located at an edge of the main FET and spaced apart from the transistor portion of the sense FET. The sense FET source pad is connected to the transistor portion of the sense FET by a sense FET probe metal. The isolation structure is configured such that the transistor portion of the sense FET and the sense FET source pad are located outside an active area of the main FET.12-23-2010
20100320531STANDING CHIP SCALE PACKAGE - A standing chip scale package is disclosed. The standing chip scale package provides electrical connection to bumped device contacts on both sides of the chip. The package is coupleable to a printed circuit board in a standing configuration such that front and back sides of the bumped chip are substantially perpendicular to a mounting surface. A process of fabricating the standing chip scale package is also disclosed.12-23-2010
20100330767MOSFET with a second poly and an inter-poly dielectric layer over gate for synchronous rectification - This invention discloses a new trenched vertical semiconductor power device that includes a capacitor formed between a conductive layer covering over an inter-dielectric layer disposed on top of a trenched gate. In a specific embodiment, the trenched vertical semiconductor power device may be a trenched metal oxide semiconductor field effect transistor (MOSFET) power device. The trenched gate is a trenched polysilicon gate and the conductive layer is a second polysilicon layer covering an inter-poly dielectric layer disposed on top of the trenched polysilicon gate. The conductive layer is further connected to a source of the vertical power device.12-30-2010
20110024884Structure of Mixed Semiconductor Encapsulation Structure with Multiple Chips and Capacitors - A semiconductor package for power converter application comprises a low-side MOSFET chip and a high-side MOSFET chip stacking one over the other. The semiconductor package may further enclose a capacitor whereas the capacitor may be a discrete component or an integrated component on chip level with the low-side MOSFET. The semiconductor package may further comprise a PIC chip to provide a complete power converter on semiconductor chip assembly package level.02-03-2011
20110024917MULTI-DIE PACKAGE - A multi-die package has a plurality of leads and first and second semiconductor dies in superimposition and bonded together defining a die stack. The die stack has opposed first and second sides, with each of the first and second semiconductor dies having gate, drain and source regions, and gate, drain and source contacts. The first opposed side has the drain contact of the second semiconductor die, which is in electrical communication with a first set of the plurality of leads. The gate, drain and source contacts of the first semiconductor die and the gate and source contacts of the second semiconductor die are disposed on the second of said opposed sides and in electrical communication with a second set of the plurality of leads. The lead for the source of the first semiconductor die may be the same as the lead for the drain of the second semiconductor die.02-03-2011
20110037120Shielded gate trench MOSFET device and fabrication - A semiconductor device embodiment includes a substrate, an active gate trench in the substrate, and an asymmetric trench in the substrate. The asymmetric trench has a first trench wall and a second trench wall, the first trench wall is lined with oxide having a first thickness, and the second trench wall is lined with oxide having a second thickness that is different from the first thickness. Another semiconductor device embodiment includes a substrate, an active gate trench in the substrate; and a source polysilicon pickup trench in the substrate. The source polysilicon pickup trench includes a polysilicon electrode, and top surface of the polysilicon electrode is below a bottom of a body region. Another semiconductor device includes a substrate, an active gate trench in the substrate, the active gate trench has a first top gate electrode and a first bottom source electrode, and a gate runner trench comprising a second top gate electrode and a second bottom source electrode. The second top gate electrode is narrower than the second bottom source electrode.02-17-2011
20110039383Shielded gate trench MOSFET device and fabrication - A method for fabricating a semiconductor device includes forming a plurality of trenches, including applying a first mask, forming a first polysilicon region in at least some of the plurality of trenches, forming a inter-polysilicon dielectric region and a termination protection region, including applying a second mask, forming a second polysilicon region in the at least some of the plurality of trenches, forming a first electrical contact to the first polysilicon region and forming a second electrical contact to the second polysilicon region, including applying a third mask, disposing a metal layer, and forming a source metal region and a gate metal region, including applying a fourth mask.02-17-2011
20110042724Trenched mosfets with part of the device formed on a (110) crystal plane - This invention discloses an improved MOSFET devices manufactured with a trenched gate by forming the sidewalls of the trench on a (110) crystal orientation of a semiconductor substrate. The trench is covering with a dielectric oxide layer along the sidewalls and the bottom surface or the termination of the trench formed along different crystal orientations of the semiconductor substrate. Special manufacturing processes such as oxide annealing process, special mask or SOG processes are implemented to overcome the limitations of the non-uniform dielectric layer growth.02-24-2011
20110042727MOSFET device with reduced breakdown voltage - A semiconductor device includes a drain, an epitaxial layer overlaying the drain, and an active region. The active region includes a body disposed in the epitaxial layer, a source embedded in the body, a gate trench extending into the epitaxial layer, a gate disposed in the gate trench, a contact trench extending through the source and at least part of the body, a contact electrode disposed in the contact trench, and an epitaxial enhancement portion disposed below the contact trench, wherein the epitaxial enhancement portion has the same carrier type as the epitaxial layer.02-24-2011
20110042742STRUCTURES OF AND METHODS OF FABRICATING TRENCH-GATED MIS DEVICES - In a trench-gated MIS device contact is made to the gate within the trench, thereby eliminating the need to have the gate material, typically polysilicon, extend outside of the trench. This avoids the problem of stress at the upper corners of the trench. Contact between the gate metal and the polysilicon is normally made in a gate metal region that is outside the active region of the device. Various configurations for making the contact between the gate metal and the polysilicon are described, including embodiments wherein the trench is widened in the area of contact. Since the polysilicon is etched back below the top surface of the silicon throughout the device, there is normally no need for a polysilicon mask, thereby saving fabrication costs.02-24-2011
20110049564Integrated schottky diode in high voltage semiconductor device - This invention discloses a method for manufacturing a semiconductor power device in a semiconductor substrate comprises an active cell area and a termination area. The method comprises the steps of a) growing and patterning a field oxide layer in the termination area and also in the active cell area on a top surface of the semiconductor substrate b) depositing and patterning a polysilicon layer on the top surface of the semiconductor substrate at a gap distance away from the field oxide layer; c) performing a blank body dopant implant to form body dopant regions in the semiconductor substrate substantially aligned with the gap area followed by diffusing the body dopant regions into body regions in the semiconductor substrate; d) implanting high concentration body-dopant regions encompassed in and having a higher dopant concentration than the body regions and e) applying a source mask to implant source regions having a conductivity opposite to the body region with the source regions encompassed in the body regions and surrounded by the high concentration body-dopant regions.03-03-2011
20110049580Hybrid Packaged Gate Controlled Semiconductor Switching Device Using GaN MESFET - A hybrid packaged gate controlled semiconductor switching device (HPSD) has an insulated-gate transistor (IGT) made of a first semiconductor die and a rectifying-gate transistor (RGT) made of a second semiconductor die. The RGT gate and source are electrically connected to the IGT source and drain respectively. The HPSD includes a package base with package terminals for interconnecting the HPSD to external environment. The IGT is die bonded atop the package base. The second semiconductor die is formed upon a composite semiconductor epi layer overlaying an electrically insulating substrate (EIS) thus creating a RGT die. The RGT die is stacked and bonded atop the IGT die via the EIS. The IGT, RGT die and package terminals are interconnected with bonding wires. Thus, the HPSD is a stacked package of IGT die and RGT die with reduced package footprint while allowing flexible placements of device terminal electrodes on the IGT.03-03-2011
20110059593Method of Integrating a MOSFET with a Capacitor - A bypass capacitor is directly integrated on top of a MOSFET chip. The capacitor comprises multi layers of conductive material and dielectric material staking on top of each other with connection vias through dielectric layer for connecting different conductive layers. The method of integrating the bypass capacitor comprises repeating steps of depositing a dielectric layer, forming connection vias through the dielectric layer, depositing a conductive layer and patterning the conductive layer.03-10-2011
20110062506Metal Oxide Semiconductor Field Effect Transistor Integrating a Capacitor - A bypass capacitor is directly integrated on top of a MOSFET chip. The capacitor comprises multi layers of conductive material and dielectric material staking on top of each other with connection vias through dielectric layer for connecting different conductive layers. The method of integrating the bypass capacitor comprises repeating steps of depositing a dielectric layer, forming connection vias through the dielectric layer, depositing a conductive layer and patterning the conductive layer.03-17-2011
20110068386DIRECT CONTACT IN TRENCH WITH THREE-MASK SHIELD GATE PROCESS - A semiconductor device and a method for making a semiconductor device are disclosed. A trench mask may be applied to a semiconductor substrate, which is etched to form trenches with three different widths. A first conductive material is formed at the bottom of the trenches. A second conductive material is formed over the first conductive material. An insulator layer separates the first and second conductive materials. A first insulator layer is deposited on top of the trenches. A body layer is formed in a top portion of the substrate. A source is formed in the body layer. A second insulator layer is applied on top of the trenches and the source. A contact mask is applied on top of the second insulator layer. Source and gate contacts are formed through the second insulator layer. Source and gate metal are formed on top of the second insulator layer.03-24-2011
20110073906High voltage MOSFET diode reverse recovery by minimizing P-body charges - This invention discloses a method for manufacturing a semiconductor power device in a semiconductor substrate comprises an active cell area and a termination area. The method comprises the steps of a) growing and patterning a field oxide layer in the termination area and also in the active cell area on a top surface of the semiconductor substrate b) depositing and patterning a polysilicon layer on the top surface of the semiconductor substrate at a gap distance away from the field oxide layer; c) performing a blank body dopant implant to form body dopant regions in the semiconductor substrate substantially aligned with the gap area followed by diffusing the body dopant regions into body regions in the semiconductor substrate; d) implanting high concentration body-dopant regions encompassed in and having a higher dopant concentration than the body regions e) applying a source mask to implant source regions having a conductivity opposite to the body region with the source regions encompassed in the body regions and surrounded by the high concentration body-dopant regions; and f) etching contact trenches into the source, body contact, and body regions.03-31-2011
20110076815Reduced mask configuration for power mosfets with electrostatic discharge (ESD) circuit protection - A semiconductor power device supported on a semiconductor substrate includes an electrostatic discharge (ESD) protection circuit disposed on a first portion of patterned ESD polysilicon layer on top of the semiconductor substrate. The semiconductor power device further includes a second portion of the patterned ESD polysilicon layer constituting a body implant ion block layer for blocking implanting body ions to enter into the semiconductor substrate below the body implant ion block layer. In an exemplary embodiment, the electrostatic discharge (ESD) polysilicon layer on top of the semiconductor substrate further covering a scribe line on an edge of the semiconductor device whereby a passivation layer is no longer required manufacturing the semiconductor device for reducing a mask required for patterning the passivation layer.03-31-2011
20110097885Mosfet using gate work function engineering for switching applications - This invention discloses a new MOSFET device. The MOSFET device has an improved operation characteristic achieved by manufacturing a MOSFET with a higher gate work function by implementing a P-doped gate in an N-MOSFET device. The P-type gate increases the threshold voltage and shifts the C-Vds characteristics. The reduced Cgd thus achieves the purpose of suppressing the shoot through and resolve the difficulties discussed above. Unlike the conventional techniques, the reduction of the capacitance Cgd is achieved without requiring complicated fabrication processes and control of the recess electrode.04-28-2011
20110101446STAGGERED COLUMN SUPERJUNCTION - A staggered column superjunction semiconductor device may include a cell region having one or more device cells. One or more device cells in the cell region include a semiconductor substrate configured to act as a drain and a semiconductor layer formed on the substrate. A first doped column may be formed in the semiconductor layer to a first depth and a second doped column may be formed in the semiconductor layer to a second depth. The first depth is greater than the second depth. The first and second columns are doped with dopants of a same second conductivity type and extend along a portion of a thickness of the semiconductor layer and are separated from each by a portion of the semiconductor layer.05-05-2011
20110103148Normally off gallium nitride field effect transistors (FET) - A heterostructure field effect transistor (HFET) gallium nitride (GaN) semiconductor power device comprises a hetero-junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The power device further comprises a source electrode and a drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero-junction structure for controlling a current flow between the source and drain electrodes in the 2DEG layer. The power device further includes a floating gate located between the gate electrode and hetero-junction structure, wherein the gate electrode is insulated from the floating gate with an insulation layer and wherein the floating gate is disposed above and padded with a thin insulation layer from the hetero-junction structure and wherein the floating gate is charged for continuously applying a voltage to the 2DEG layer to pinch off the current flowing in the 2DEG layer between the source and drain electrodes whereby the HFET semiconductor power device is a normally off device.05-05-2011
20110108998USE OF DISCRETE CONDUCTIVE LAYER IN SEMICONDUCTOR DEVICE TO RE-ROUTE BONDING WIRES FOR SEMICONDUCTOR DEVICE PACKAGE - A semiconductor package assembly may include a lead frame having a die bonding pad and plurality of leads coupled to the first die bonding pad. A vertical semiconductor device may be bonded to the die bonding pad. The device may have a conductive pad electrically connected to one lead through a first bond wire. An electrically isolated conductive trace may be formed from a layer of conductive material of the first semiconductor device. The conductive trace provides an electrically conductive path between the first bond wire and a second bond wire. The conductive path may either pass underneath a third bond wire thereby avoiding the third bond wire crossing another bond wire, or the conductive path may result in a reduced length for the first and second bond wires that is less than a predetermined maximum length.05-12-2011
20110127586Lateral super junction device with high substrate-gate breakdown and built-in avalanche clamp diode - A lateral super junction JFET is formed from stacked alternating P type and N type semiconductor layers over a P-epi layer supported on an N+ substrate. An N+ drain column extends down through the super junction structure and the P-epi to connect to the N+ substrate to make the device a bottom drain device. N+ source column and P+ gate column extend through the super junction but stop at the P-epi layer. A gate-drain avalanche clamp diode is formed from the bottom the P+ gate column through the P-epi to the N+ drain substrate.06-02-2011
20110127606Lateral super junction device with high substrate-drain breakdwon and built-in avalanche clamp diode - This invention discloses configurations and methods to manufacture lateral power device including a super junction structure with an avalanche clamp diode formed between the drain and the gate. The lateral super-junction structure reduces on-resistance, while the structural enhancements, including an avalanche clamping diode and an N buffer region, increase the breakdown voltage between substrate and drain and improve unclamped inductive switching (UIS) performance.06-02-2011
20110140167Nanotube Semiconductor Devices - A method for forming a semiconductor device includes forming a nanotube region using a thin epitaxial layer formed on the sidewall of a trench in the semiconductor body. The thin epitaxial layer has uniform doping concentration. In another embodiment, a first thin epitaxial layer of the same conductivity type as the semiconductor body is formed on the sidewall of a trench in the semiconductor body and a second thin epitaxial layer of the opposite conductivity type is formed on the first epitaxial layer. The first and second epitaxial layers have uniform doping concentration. The thickness and doping concentrations of the first and second epitaxial layers and the semiconductor body are selected to achieve charge balance. In one embodiment, the semiconductor body is a lightly doped P-type substrate. A vertical trench MOSFET, an IGBT, a Schottky diode and a P-N junction diode can be formed using the same N-Epi/P-Epi nanotube structure.06-16-2011
20110140194Enhancing Schottky breakdown voltage (BV) without affecting an integrated Mosfet-Schottky device layout - This invention discloses a semiconductor power device that includes an active cell area having a plurality of power transistor cells. Each of said power transistor cells has a planar Schottky diode that includes a Schottky junction barrier metal covering areas above gaps between separated body regions between two adjacent power transistor cells. The separated body regions further provide a function of adjusting a leakage current of said Schottky diode in each of said power transistor cells. Each of the planar Schottky diodes further includes a Shannon implant region disposed in a gap between the separated body regions of two adjacent power transistor cells for further adjusting a leakage current of said Schottky diode. Each of the power transistor cells further includes heavy body doped regions in the separated body regions next to source regions surrounding said Schottky diode forming a junction barrier Schottky (JBS) pocket region.06-16-2011
20110140228Method of Filling Large Deep Trench with High Quality Oxide for Semiconductor Devices - A method is disclosed for creating a semiconductor device structure with an oxide-filled large deep trench (OFLDT) portion having trench size TCS and trench depth TCD. A bulk semiconductor layer (BSL) is provided with a thickness BSLT>TCD. A large trench top area (LTTA) is mapped out atop BSL with its geometry equal to OFLDT. The LTTA is partitioned into interspersed, complementary interim areas ITA-A and ITA-B. Numerous interim vertical trenches of depth TCD are created into the top BSL surface by removing bulk semiconductor materials corresponding to ITA-B. The remaining bulk semiconductor materials corresponding to ITA-A are converted into oxide. If any residual space is still left between the so-converted ITA-A, the residual space is filled up with oxide deposition. Importantly, the geometry of all ITA-A and ITA-B should be configured simple and small enough to facilitate fast and efficient processes of oxide conversion and oxide filling.06-16-2011
20110147830METHOD OF FORMING A SELF-ALIGNED CHARGE BALANCED POWER DMOS - Self-aligned charge balanced semiconductor devices and methods for forming such devices are disclosed. One or more planar gates are formed over a semiconductor substrate of a first conductivity type. One or more deep trenches are etched in the semiconductor self-aligned to the planar gates. The trenches are filled with a semiconductor material of a second conductivity type such that the deep trenches are charge balanced with the adjacent regions of the semiconductor substrate This process can form self-aligned charge balanced devices with a cell pitch less than 12 microns.06-23-2011
20110151628Configuration of gate to drain (GD) clamp and ESD protection circuit for power device breakdown protection - A semiconductor power device supported on a semiconductor substrate comprising a plurality of transistor cells each having a source and a drain with a gate to control an electric current transmitted between the source and the drain. The semiconductor further includes a gate-to-drain (GD) clamp termination connected in series between the gate and the drain further includes a plurality of back-to-back polysilicon diodes connected in series to a silicon diode includes parallel doped columns in the semiconductor substrate wherein the parallel doped columns having a predefined gap. The doped columns further include a U-shaped bend column connect together the ends of parallel doped columns with a deep doped well disposed below and engulfing the U-shaped bend.06-23-2011

Patent applications by Anup Bhalla, Santa Clara, CA US