ALPHA & OMEGA SEMICONDUCTOR, INC. Patent applications |
Patent application number | Title | Published |
20140085760 | Active Clamp Protection Circuit For Power Semiconductor Device For High Frequency Switching - A protection circuit for a power transistor includes a first transistor connected in parallel with the power transistor and having a control terminal connected to a first power supply voltage through a first resistive element; and a first set of diodes connected between a first terminal and a control terminal of the first transistor. In operation, the voltage at the first terminal of the first transistor is clamped to a clamp voltage and the first transistor is turned on to conduct current in a forward conduction mode when an over-voltage condition occurs at a first terminal of the power transistor. | 03-27-2014 |
20140049293 | Three-Dimensional High Voltage Gate Driver Integrated Circuit - A three-dimensional (3D) gate driver integrated circuit includes a high-side integrated circuit stacked on a low-side integrated circuit where the high-side integrated circuit and the low-side integrated circuit are interconnected using through-silicon vias (TSV). As thus formed, the high-side integrated circuit and the low-side integrated circuit can be formed without termination regions and without buried layers. The 3D gate driver integrated circuit improves ease of high voltage integration and improves the ruggedness and reliability of the gate driver integrated circuit | 02-20-2014 |
20130049102 | Buried field ring field effect transistor (BUF-FET) integrated with cells implanted with hole supply path - This invention discloses a semiconductor power device formed in a semiconductor substrate comprises a highly doped region near a top surface of the semiconductor substrate on top of a lightly doped region. The semiconductor power device further comprises a body region, a source region and a gate disposed near the top surface of the semiconductor substrate and a drain disposed at a bottom surface of the semiconductor substrate. The semiconductor power device further comprises source trenches opened into the highly doped region filled with a conductive trench filling material in electrical contact with the source region near the top surface. The semiconductor power device further comprises a buried field ring regions disposed below the source trenches and doped with dopants of opposite conductivity from the highly doped region. In an alternate embodiment, the semiconductor power device further comprises doped regions surrounded the sidewalls of the source trenches and doped with a dopant of a same conductivity type of the buried field ring regions to function as a charge supply path. | 02-28-2013 |
20130020671 | Termination of high voltage (HV) devices with new configurations and methods - This invention discloses a semiconductor power device disposed in a semiconductor substrate comprising a heavily doped region formed on a lightly doped region and having an active cell area and an edge termination area. The edge termination area comprises a plurality of termination trenches formed in the heavily doped region with the termination trenches lined with a dielectric layer and filled with a conductive material therein. The edge termination further includes a plurality of buried guard rings formed as doped regions in the lightly doped region of the semiconductor substrate immediately adjacent to the termination trenches. | 01-24-2013 |
20130020635 | Semiconductor device with field threshold MOSFET for high voltage termination - This invention discloses a semiconductor power device disposed in a semiconductor substrate comprising a lightly doped layer formed on a heavily doped layer and having an active cell area and an edge termination area. The edge termination area comprises a plurality P-channel MOSFETs. By connecting the gate to the drain electrode, the P-channel MOSFET transistors formed on the edge termination are sequentially turned on when the applied voltage is equal to or greater than the threshold voltage Vt of the P-channel MOSFET transistors, thereby optimizing the voltage blocked by each region. | 01-24-2013 |
20130015494 | Nanotube Semiconductor Devices and Nanotube Termination Structures - A termination structure for a semiconductor device includes an array of termination cells formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In other embodiments, semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. | 01-17-2013 |
20120329238 | Method For Forming A Transient 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. | 12-27-2012 |
20120282762 | Method For Forming Gallium Nitride Semiconductor Device With Improved Forward Conduction - A method for forming a gallium nitride based semiconductor diode includes forming Schottky contacts on the upper surface of mesas formed in a semiconductor body formed on a substrate. Ohmic contacts are formed on the lower surface of the semiconductor body. In one embodiment, an insulating layer is formed over the Schottky and ohmic contacts and vias are formed in the insulating layer to the Schottky and ohmic contacts to form the anode and cathode electrodes. In another embodiment, vias are formed in the insulating layer to the Schottky contacts and vias are formed in the semiconductor body to the ohmic contacts. An anode electrode is formed in electrical contact with the Schottky contacts. A cathode electrode is formed in electrical contact with the ohmic contacts on the backside of the substrate. | 11-08-2012 |
20120187481 | Vertical Trench LDMOS Transistor - A vertical trench LDMOS transistor includes a semiconductor layer of a first conductivity type; a first trench formed in the semiconductor layer and filled with a trench dielectric and a trench gate is formed in the first trench; a body region of a second conductivity type formed in the semiconductor layer adjacent the first trench; a source region formed in the body region and adjacent the first trench; a planar gate insulated from the semiconductor layer by a second gate dielectric layer and overlying the body region; and a drain drift region formed in the semiconductor layer. The planar gate forms a lateral channel in the body region between the source region and the drain drift region, and the trench gate in the first trench forms a vertical channel in the body region along the sidewall of the first trench between the source region and the semiconductor layer. | 07-26-2012 |
20120129328 | MULTIPLE LAYER BARRIER METAL FOR DEVICE COMPONENT FORMED IN CONTACT TRENCH - A semiconductor device formed on a semiconductor substrate may include a component formed in a contact trench located in an active cell region. The component may comprise a barrier metal deposited on a bottom and portions of sidewalls of the contact trench and a tungsten plug deposited in a remaining portion of the contact trench. The barrier metal may comprise first and second metal layers. The first metal layer may be proximate to the sidewall and the bottom of the contact trench. The first metal layer may include a nitride. The second metal layer may be between the first metal layer and the tungsten plug and between the tungsten plug and the sidewall. The second metal layer covers portions of the sidewalls of not covered by the first metal layer. | 05-24-2012 |
20110278589 | Gallium Nitride Semiconductor Device With Improved Forward Conduction - A gallium nitride based semiconductor diode includes a substrate, a semiconductor body including a first heavily doped GaN layer and a second lightly doped GaN layer. The semiconductor body includes mesas projecting upwardly from a lower surface where each of the mesas includes the second GaN layer and a portion of the first GaN layer. Schottky contacts are formed on the upper surface of the mesas and ohmic contacts are formed on the lower surface of the semiconductor body. An insulating layer is formed over the Schottky and ohmic contacts. Vias are formed in the insulating layer to the Schottky contacts and vias are formed in the semiconductor body to the Ohmic contacts. An anode electrode is formed in a first metal pad in electrical contact with the Schottky contacts. A cathode electrode is formed in a second metal pad in electrical contact with the ohmic contacts. | 11-17-2011 |
20110140167 | 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. | 06-16-2011 |
20110095361 | MULTIPLE LAYER BARRIER METAL FOR DEVICE COMPONENT FORMED IN CONTACT TRENCH - A semiconductor device formed on a semiconductor substrate may include a component formed in a contact trench located in an active cell region. The component may comprise a barrier metal deposited on a bottom and portions of sidewalls of the contact trench and a tungsten plug deposited in a remaining portion of the contact trench. The barrier metal may comprise first and second metal layers. The first metal layer may be proximate to the sidewall and the bottom of the contact trench. The first metal layer may include a nitride. The second metal layer may be between the first metal layer and the tungsten plug and between the tungsten plug and the sidewall. The second metal layer covers portions of the sidewalls of not covered by the first metal layer. | 04-28-2011 |
20100317158 | Method 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 |
20100314659 | Nanotube 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 |
20100276779 | Transient 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 |
20100207232 | Gallium Nitride Semiconductor Device With Improved Forward Conduction - A gallium nitride based semiconductor diode includes a substrate, a semiconductor body including a first heavily doped GaN layer and a second lightly doped GaN layer. The semiconductor body includes mesas projecting upwardly from a lower surface where each of the mesas includes the second GaN layer and a portion of the first GaN layer. Schottky contacts are formed on the upper surface of the mesas and ohmic contacts are formed on the lower surface of the semiconductor body. An insulating layer is formed over the Schottky and ohmic contacts and vias are formed in the insulating layer to the Schottky and Ohmic contacts. A first metal pad is formed in a third metal layer and over vias to the Schottky contacts to form an anode electrode. A second metal pad is formed in the third metal layer and over vias to the ohmic contacts to form a cathode electrode. | 08-19-2010 |
20100207166 | Gallium Nitride Heterojunction Schottky Diode - A gallium nitride based semiconductor diode includes a substrate, a GaN layer formed on the substrate, an AlGaN layer formed on the GaN layer where the GaN layer and the AlGaN layer forms a cathode region of the diode, a metal layer formed on the AlGaN layer forming a Schottky junction therewith where the metal layer forms an anode electrode of the diode, and a high barrier region formed in the top surface of the AlGaN layer and positioned under an edge of the metal layer. The high barrier region has a higher bandgap energy than the AlGaN layer or being more resistive than the AlGaN layer. | 08-19-2010 |
20100190307 | HIGH 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 |