Abstract: Various structures and methods for improving the performance of trench-shielded power semiconductor devices and the like are described. An exemplary device comprises a semiconductor region having a surface, a first area of the semiconductor region, a well region of a first conductivity type disposed in the semiconductor region and around the first area, and a plurality of trenches extending in a semiconductor region. Each trench haves a first end disposed in a first portion of the well region, a second end disposed in a second portion of the well region, and a middle portion between the first and second ends and disposed in the first area. Each trench further having opposing sidewalls lined with a dielectric layer, and a conductive electrode disposed on at least a portion of the dielectric layer.

Abstract: Methods of manufacturing power semiconductor devices include forming an epitaxial and dielectric layer, patterning and etching the dielectric layer, forming a first oxide layer, forming a first conductive layer on top of the first oxide layer, etching the first conductive layer away inside an active trench, forming a second oxide layer and second conductive layer. The second conductive layer does not extend completely over the first conductive layer in a first region outside of the active trench. The methods further include forming a third oxide layer over the second conductive layer, etching a first opening through the third oxide layer exposing the second conductive layer outside the active trench, etching a second opening through the second oxide layer outside the active trench in the first region exposing the first conductive layer but not the second conductive layer, and filling the first and second openings with conductive material.

Abstract: 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.

Abstract: Methods of manufacturing power semiconductor devices include forming an epitaxial and dielectric layer, patterning and etching the dielectric layer, forming a first oxide layer, forming a first conductive layer on top of the first oxide layer, etching the first conductive layer away inside an active trench, forming a second oxide layer and second conductive layer. The second conductive layer does not extend completely over the first conductive layer in a first region outside of the active trench. The methods further include forming a third oxide layer over the second conductive layer, etching a first opening through the third oxide layer exposing the second conductive layer outside the active trench, etching a second opening through the second oxide layer outside the active trench in the first region exposing the first conductive layer but not the second conductive layer, and filling the first and second openings with conductive material.

Abstract: Methods of manufacturing power semiconductor devices include forming trenches in a substrate, depositing a shield oxide layer that conforms to the trenches, depositing a gate polysilicon layer into the trenches, etching the gate polysilicon layer so that the gate polysilicon layer is recessed in the trench, etching the shield oxide layer so that the shield oxide layer is recessed in the trench and lower than the gate polysilicon layer, depositing a layer of gate oxide across the top of the substrate, sidewalls of the trenches and troughs inside the trenches leaving a recess, depositing shield polysilicon in the recess, etching the shield polysilicon layer so that the shield polysilicon layer is recessed in the trench and higher than the gate polysilicon layer, forming a well region, and forming a source region. The well region can be formed with a ?p-well implant. The source region can be performed with an n+ source implant.

Abstract: 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.

Abstract: 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.

Abstract: A semiconductor power device includes a drift region of a first conductivity type, a well region extending above the drift region and having a second conductivity type opposite the first conductivity type, active trenches extending through the well region and into the drift region where the active trenches define an active area. Inside each of the active trenches is formed a first conductive gate electrode disposed along and insulated from a first trench sidewall, a second conductive gate electrode disposed along and insulated from a second trench sidewall, and a conductive shield electrode disposed between the first and second conductive gate electrodes, wherein the shield electrode is insulated from and extends deeper inside the trench than the first and second conductive gate electrodes. The device also includes source regions having the first conductivity type formed inside the well region and adjacent the active trenches.

Abstract: A semiconductor power device includes active trenches that define an active area and an edge area that is located outside of the active area. The active trenches include a lower shield poly, an upper gate poly, a first oxide layer and a second oxide layer wherein the first oxide layer separates the lower shield poly from the upper gate poly and the second oxide layer covers the upper gate poly. The lower shield poly, upper gate poly, first oxide layer and second oxide layer conform to the shapo of the active trench and extend from the active trench to a surface of the edge area. The edge area includes a first opening that extends through the first oxide layer to the lower shield poly and a second opening that extends through the second oxide layer to the upper gate poly.

Abstract: 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.

Abstract: 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.

Abstract: An electrical device on a single semiconductor substrate includes: an open base vertical PNP transistor placed in parallel with a wide bandgap, high voltage diode wherein the PNP transistor has a P doped collector region, an N-doped base layer, an N doped buffer layer, and a P doped emitter layer.

Abstract: 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.

Abstract: A method and device for protecting wide bandgap devices from failing during suppression of voltage transients. An improvement in avalanche capability is achieved by placing one or more diodes, or a PNP transistor, across the blocking junction of the wide bandgap device.

Abstract: 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.

Abstract: 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.

Abstract: Various structures and methods for improving the performance of trench-shielded power semiconductor devices and the like are described.

Abstract: 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.

Abstract: Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed.

Abstract: Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed.