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Thomas E. Grebs

Thomas E. Grebs, Mountain Top, PA US

Patent application numberDescriptionPublished
20090111231Method for Forming Shielded Gate Field Effect Transistor Using Spacers - A trench is formed in a semiconductor region. A dielectric layer lining sidewalls and bottom surface of the trench is formed. The dielectric layer is thicker along lower sidewalls and the bottom surface than along upper sidewalls of the trench. After forming the dielectric layer, a lower portion of the trench is filled with a shield electrode. Dielectric spacers are formed along the upper trench sidewalls. After forming the dielectric spacers, an inter-electrode dielectric (IED) is formed in the trench over the shield electrode. After forming the IED, the dielectric spacers are removed.04-30-2009
20100155839LATERAL MOSFET WITH SUBSTRATE DRAIN CONNECTION - In one form a lateral MOSFET includes an active gate positioned laterally between a source region and a drain region, the drain region extending from an upper surface of a monocrystalline semiconductor body to a bottom surface of the monocrystalline semiconductor body, and a non-active gate positioned above the drain region. In another form the lateral MOSFET includes a gate positioned laterally between a source region and a drain region, the drain region extending from an upper surface of a monocrystalline semiconductor body to a bottom surface of the monocrystalline semiconductor body, the source region and the drain region being of a first conductivity type, a heavy body region of a second conductivity type in contact with and below the source region, and the drain region comprising a lightly doped drain (LDD) region proximate an edge of the gate and a sinker extending from the upper surface of the monocrystalline body to the bottom surface of the monocrystalline semiconductor body.06-24-2010
20100314707Reduced Process Sensitivity of Electrode-Semiconductor Rectifiers - Disclosed are semiconductor devices and methods of making semiconductor devices. An exemplary embodiment comprises a semiconductor layer of a first conductivity type having a first surface, a second surface, and a graded net doping concentration of the first conductivity type within a portion of the semiconductor layer. The graded portion is located adjacent to the top surface of the semiconductor layer, and the graded net doping concentration therein decreasing in value with distance from the top surface of the semiconductor layer. The exemplary device also comprises an electrode disposed at the first surface of the semiconductor layer and adjacent to the graded portion.12-16-2010
20110212586Method for Forming Shielded Gate Field Effect Transistors - A method for forming a field effect transistor includes forming a trench in a semiconductor region and forming a dielectric layer lining lower sidewalls and bottom surface of the trench. After forming the dielectric layer, a lower portion of the trench is filled with a shield electrode. An inter-electrode dielectric (IED) is formed in the trench over the shield electrode by carrying out a steam ambient oxidation and carrying out a dry ambient oxidation. A gate electrode is formed in an upper portion of the trench. The gate electrode may be insulated from the shield electrode by the IED.09-01-2011
20120018803LATERAL DRAIN MOSFET WITH SUBSTRATE DRAIN CONNECTION - In one form a lateral MOSFET includes an active gate positioned laterally between a source region and a drain region, the drain region extending from an upper surface of a monocrystalline semiconductor body to a bottom surface of the monocrystalline semiconductor body, and a non-active gate positioned above the drain region. In another form the lateral MOSFET includes a gate positioned laterally between a source region and a drain region, the drain region extending from an upper surface of a monocrystalline semiconductor body to a bottom surface of the monocrystalline semiconductor body, the source region and the drain region being of a first conductivity type, a heavy body region of a second conductivity type in contact with and below the source region, and the drain region comprising a lightly doped drain (LDD) region proximate an edge of the gate and a sinker extending from the upper surface of the monocrystalline body to the bottom surface of the monocrystalline semiconductor body.01-26-2012
20120037982REDUCED PROCESS SENSITIVITY OF ELECTRODE-SEMICONDUCTOR RECTIFIERS - Disclosed are semiconductor devices and methods of making semiconductor devices. An exemplary embodiment comprises a semiconductor layer of a first conductivity type having a first surface, a second surface, and a graded net doping concentration of the first conductivity type within a portion of the semiconductor layer. The graded portion is located adjacent to the top surface of the semiconductor layer, and the graded net doping concentration therein decreasing in value with distance from the top surface of the semiconductor layer. The exemplary device also comprises an electrode disposed at the first surface of the semiconductor layer and adjacent to the graded portion.02-16-2012
20120058615Method of Forming Shielded Gate Power Transistor Utilizing Chemical Mechanical Planarization - A method of forming a shielded gate field effect transistor includes: forming a plurality of active gate trenches in a silicon region; lining lower sidewalls and bottom of the active gate trenches with a shield dielectric; using a CMP process, filling a bottom portion of the active gate trenches with a shield electrode comprising polysilicon; forming an interpoly dielectric (IPD) over the shield electrode in the active gate trenches; lining upper sidewalls of the active gate trenches with a gate dielectric; and forming a gate electrode over the IPD in an upper portion of the active gate trenches.03-08-2012

Patent applications by Thomas E. Grebs, Mountain Top, PA US

Thomas E. Grebs, Mountaintop, PA US

Patent application numberDescriptionPublished
20080199997Methods of Forming Inter-poly Dielectric (IPD) Layers in Power Semiconductor Devices - A method for forming power semiconductor devices having an inter-electrode dielectric (IPD) layer inside a trench includes providing a semiconductor substrate with a trench, lining the sidewalls and bottom of the trench with a first layer of dielectric material, filling the trench with a first layer of conductive material to form a first electrode, recessing the first layer of dielectric material and the first layer of conductive material to a first depth inside the trench, forming a layer of polysilicon material on a top surface of the dielectric material and conductive material inside the trench, oxidizing the layer of polysilicon material, and forming a second electrode inside the trench atop the oxidized layer and isolated from trench sidewalls by a second dielectric layer. The oxidation step can be enhanced by either chemically or physically altering the top portion polysilicon such as by implanting impurities.08-21-2008
20090230465Trench-Gate Field Effect Transistors and Methods of Forming the Same - A field effect transistor includes a body region of a first conductivity type over a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminates within the semiconductor region. At least one conductive shield electrode is disposed in the gate trench. A gate electrode is disposed in the gate trench over but insulated from the at least one conductive shield electrode. A shield dielectric layer insulates the at lease one conductive shield electrode from the semiconductor region. A gate dielectric layer insulates the gate electrode from the body region. The shield dielectric layer is formed such that it flares out and extends directly under the body region.09-17-2009
20100200910Semiconductor Devices with Stable and Controlled Avalanche Characteristics and Methods of Fabricating the Same - Disclosed are semiconductor devices with breakdown voltages that are more controlled and stable after repeated exposure to breakdown conditions than prior art devices. The disclosed devices can be used to provide secondary circuit functions not previously contemplated by the prior art.08-12-2010
20100207205Structures and Methods for Improving Trench-Shielded Semiconductor Devices and Schottky Barrier Rectifier Devices - Various structures and methods for improving the performance of trench-shielded power semiconductor devices and the like are described.08-19-2010
20100237415Semiconductor Power Device Having a Top-side Drain Using a Sinker Trench - A semiconductor power device includes a plurality of groups of stripe-shaped trenches extending in a silicon region over a substrate, and a contiguous sinker trench completely surrounding each group of the plurality of stripe-shaped trenches so as to isolate the plurality of groups of stripe-shaped trenches from one another. The contiguous sinker trench extends from a top surface of the silicon region through the silicon region and terminates within the substrate. The contiguous sinker trench is lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the contiguous sinker trench makes electrical contact with the substrate along the bottom of the contiguous sinker trench and makes electrical contact with an interconnect layer along the top of the contiguous sinker trench.09-23-2010
20100258862TRENCH-GATE FIELD EFFECT TRANSISTOR WITH CHANNEL ENHANCEMENT REGION AND METHODS OF FORMING THE SAME - A field effect transistor includes a body region of a first conductivity type in a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminating within the semiconductor region. A source region of the second conductivity type extends in the body region adjacent the gate trench. The source region and an interface between the body region and the semiconductor region define a channel region therebetween which extends along the gate trench sidewall. A channel enhancement region of the second conductivity type is formed adjacent the gate trench. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region.10-14-2010
20110177662Method of Forming Trench-Gate Field Effect Transistors - A method of forming a field effect transistor includes: forming a trench in a semiconductor region; forming a shield electrode in the trench; performing an angled sidewall implant of impurities of the first conductivity type to form a channel enhancement region adjacent the trench; forming a body region of a second conductivity type in the semiconductor region; and forming a source region of the first conductivity type in the body region, the source region and an interface between the body region and the semiconductor region defining a channel region therebetween, the channel region extending along the trench sidewall. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region.07-21-2011
20110260241Semiconductor Power Device Having a Top-side Drain Using a Sinker Trench - A semiconductor power device includes a plurality of groups of stripe-shaped gate trenches extending in a silicon region over a substrate, and a plurality of stripe-shaped sinker trenches each extending between two adjacent groups of the plurality of groups of stripe-shaped gate trenches. The plurality of stripe-shaped sinker trenches extend from a top surface of the silicon region through the silicon region and terminate within the substrate. The plurality of stripe-shaped sinker trenches are lined with an insulator along the sinker trench sidewalls so that a conductive material filling each sinker trench makes electrical contact with the substrate along the bottom of the sinker trench and makes electrical contact with an interconnect layer along the top of the sinker trench.10-27-2011
20120104490Trench-Gate Field Effect Transistors and Methods of Forming the Same - A field effect transistor includes a body region of a first conductivity type over a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminates within the semiconductor region. At least one conductive shield electrode is disposed in the gate trench. A gate electrode is disposed in the gate trench over but insulated from the at least one conductive shield electrode. A shield dielectric layer insulates the at lease one conductive shield electrode from the semiconductor region. A gate dielectric layer insulates the gate electrode from the body region. The shield dielectric layer is formed such that it flares out and extends directly under the body region.05-03-2012
20120153384Semiconductor Power Device Having A Top-side Drain Using A Sinker Trench - A semiconductor package device houses a die which comprises a power device, and the die further includes a silicon region over a substrate, a first plurality of trenches extending in the silicon region; a contiguous sinker trench extending along the perimeter of the die so as to completely surround the first plurality of trenches, the sinker trench extending from a top surface of the die through the silicon region, the sinker trench being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the sinker trench makes electrical contact with the substrate along the bottom of the sinker trench and makes electrical contact with an interconnect layer along the top of the sinker trench; and a plurality of interconnect balls arranged in a grid array, an outer group of the plurality of interconnect balls electrically connecting to the conductive material in the sinker trench.06-21-2012

Patent applications by Thomas E. Grebs, Mountaintop, PA US

Thomas E. Grebs, South Jordan, UT US

Patent application numberDescriptionPublished
20110309469Trench MOS Barrier Schottky Rectifier With A Planar Surface Using CMP Techniques - High Efficiency Diode (HED) rectifiers with improved performance including reduced reverse leakage current, reliable solderability properties, and higher manufacturing yields are fabricated by minimizing topography variation at various stages of fabrication. Variations in the topography are minimized by using a CMP process to planarize the HED rectifier after the field oxide, polysilicon and/or solderable top metal are formed.12-22-2011
20110309470Trench MOS Barrier Schottky Rectifier With A Planar Surface Using CMP Techniques - High Efficiency Diode (HED) rectifiers with improved performance including reduced reverse leakage current, reliable solderability properties, and higher manufacturing yields are fabricated by minimizing topography variation at various stages of fabrication. Variations in the topography are minimized by using a CMP process to planarize the HED rectifier after the field oxide, polysilicon and/or solderable top metal are formed.12-22-2011

Thomas E. Grebs US

Patent application numberDescriptionPublished
20120220091METHODS OF MAKING POWER SEMICONDUCTOR DEVICES WITH THICK BOTTOM OXIDE LAYER - A method for forming thick oxide at the bottom of a trench formed in a semiconductor substrate includes forming a conformal oxide film by a sub-atmospheric chemical vapor deposition process that fills the trench and covers a top surface of the substrate. The method also includes etching the oxide film off the top surface of the substrate and inside the trench to leave a substantially flat layer of oxide having a target thickness at the bottom of the trench.08-30-2012