Wolfspeed, Inc.

Cree Gmbh

Daniel Jenner Lichtenwalner

Sei-Hyung Ryu

Edward Robert Van Brunt

Woongsun Kim

Naeem Islam

Lin Cheng

Vipindas Pala

John Williams Palmour

Anant Kumar Agarwal

Brett Hull

Shadi Sabri

Joe W McPherson

Kijeong Han

Alexander V Suvorov

Qingchun Zhang

Brice McPherson

Thomas E Harrington, Iii

Matt N McCain

Arman Ur Rashid

Scott Thomas Allen

Sarit Dhar

Jason Gurganus

Craig Capell

Madankumar Sampath

Satyaki Ganguly

Erik Maki

Matthew N McCain

A vertical semiconductor and method for fabricating the same is disclosed. In one embodiment, fabrication entails providing a precursor comprising a substrate and a drift region over the substrate. A plurality of trenches is etched into the drift region from a top surface of the drift region such that a plurality of mesas remains in an upper portion of the drift region. The plurality of trenches is then filled with a first material. A vertical semiconductor device includes a plurality of mesas extends from an upper portion of the drift region, wherein there are no regrowth interfaces between the drift region and the plurality of mesas. A first material fills the trenches between each one of the plurality of mesas. At least one first contact over at least one of the plurality of mesas. At least one second contact over a bottom surface of the substrate.

Vertical power devices having mesas and etched trenches therebetween

A power semiconductor device includes a semiconductor layer structure comprising a drift region of a first conductivity type, and a gate trench extending into the drift region. The gate trench includes sidewalls and a bottom surface therebetween. A bottom shielding structure of a second conductivity type is provided under the bottom surface of the gate trench. First and second support shielding structures of the second conductivity type extend into the drift region on opposing sides of the gate trench and are spaced apart from the sidewalls thereof. A material composition, distance of extension into the drift region relative to a surface of the semiconductor layer structure, and/or dopant concentration of the bottom shielding structure may be different from that of the first and second support shielding structures. Related devices and fabrication methods are also discussed.

Support shield structures for trenched semiconductor devices

A vertical semiconductor device includes a substrate, a drift region over the substrate, an upper region on the drift region, a top surface over the upper region and being substantially planar, and a series of implants of a second dopant in the upper region, such that each implant of the series of implants is located at a different depth below the top surface. The series of implants forms at least two gate region. The substrate and the drift region are doped with a first dopant of a first polarity. The second dopant has a second polarity opposite that of the first polarity. At least a portion of a channel region is provided between the at least two gate regions, and a conducting gap is defined within the channel region and between opposing sidewalls of the at least two gate regions.

Vertical power devices fabricated using implanted methods

Semiconductor devices and methods of forming the devices are provided. Semiconductor devices include a semiconductor layer structure comprising a trench in an upper surface thereof, a dielectric layer in a lower portion of the trench, and a gate electrode in the trench and on the dielectric layer opposite the semiconductor layer structure. The trench may include rounded upper corner and a rounded lower corner. A center portion of a top surface of the dielectric layer may be curved, and the dielectric layer may be on opposed sidewalls of the trench. The dielectric layer may include a bottom dielectric layer on a bottom surface of the trench and on lower portions of the sidewalls of the trench and a gate dielectric layer on upper portions of the sidewalls of the trench and on the bottom dielectric layer.

Power semiconductor devices including a trenched gate and methods of forming such devices

Semiconductor devices and methods of forming a semiconductor device that includes a polysilicon layer that may improve device reliability and/or a functioning of the device. An example device may include a wide band-gap semiconductor layer structure including a drift region that has a first conductivity type; a plurality of gate trenches in an upper portion of the semiconductor layer structure, each gate trench having a bottom surface, a first sidewall, a second sidewall, and an upper opening; and a plurality of polysilicon layers, each polysilicon layer on the second sidewall of a respective gate trench.

Trench bottom shielding methods and approaches for trenched semiconductor device structures

A power semiconductor device includes a semiconductor layer structure comprising a wide bandgap semiconductor material. The semiconductor layer structure includes a drift region of a first conductivity type and a plurality of fin structures protruding from the drift region. The fin structures comprise respective source regions of the first conductivity type and respective channel regions between the respective source regions and the drift region. Related devices and methods are also discussed.

FinFET power semiconductor devices

Strategic placement and patterning of electrodes, vias, and metal runners can significantly reduce strain in a power semiconductor die. By modifying the path defining electrodes, vias, and metal runners, as well as patterning the material layers thereof, strain can be better managed to increase reliability of a power semiconductor die.

Power semiconductor device with reduced strain

Power switching devices include a semiconductor layer structure, a plurality of unit cell transistors that are electrically connected in parallel, each unit cell transistor including a gate finger that has a longitudinal axis that extends in a first direction on the semiconductor layer structure, the gate fingers spaced apart from each other along a second direction, and a gate connector having a longitudinal axis that extends in the second direction, the gate connector connected to the gate fingers of the plurality of unit cell transistors.

Conduction enhancement layers for electrical contact regions in power devices

Semiconductor devices and methods of forming a semiconductor device that includes a deep shielding pattern that may improve a reliability and/or a functioning of the device. An example method may include forming a wide band-gap semiconductor layer structure on a substrate, the semiconductor layer structure including a drift region that has a first conductivity type; forming a plurality of gate trenches in an upper portion of the semiconductor layer structure, the gate trenches spaced apart from each other, each gate trench having a bottom surface, a first sidewall, a second sidewall, and an upper opening; forming an obstruction over a portion of each gate trench that partially obscures the upper opening; and implanting dopants having a second conductivity type that is opposite the first conductivity type into the bottom surfaces of the gate trenches, where the dopants implanted into the bottom surface of the gate trenches form deep shielding patterns.

Sidewall dopant shielding methods and approaches for trenched semiconductor device structures

A vertical semiconductor device includes one or more of a substrate, a buffer layer over the substrate, one or more drift layers over the buffer layer, and a spreading layer over the one or more drift layers.

Vertical semiconductor device with improved ruggedness

A power semiconductor device comprises a semiconductor layer structure comprising a drift region that comprises a wide band-gap semiconductor material that has a first conductivity type, a well region that has a second conductivity type, and a source region that has the first conductivity type in an upper portion of the well region and a gate trench in an upper portion of the semiconductor layer structure and comprising a portion obliquely angled in plan view. Sidewalls of the gate trench may extend along substantially the same crystal plane in the semiconductor layer structure.

Power semiconductor devices including angled gate trenches

A transistor semiconductor die includes a drift layer, a first dielectric layer, a first metallization layer, a second dielectric layer, a second metallization layer, a first plurality of electrodes, and a second plurality of electrodes. The first dielectric layer is over the drift layer. The first metallization layer is over the first dielectric layer such that at least a portion of the first metallization layer provides a first contact pad. The second dielectric layer is over the first metallization layer. The second metallization layer is over the second dielectric layer such that at least a portion of the second metallization layer provides a second contact pad and the second metallization layer at least partially overlaps the first metallization layer. The transistor semiconductor die is configured to selectively conduct current between the first contact pad and a third contact pad based on signals provided at the second contact pad.

Transistor semiconductor die with increased active area

A power semiconductor device includes semiconductor layer structure comprising a semiconductor drift region of a first conductivity type and an edge termination region comprising a plurality of guard rings of a second conductivity type. The guard rings extend into a surface of the semiconductor drift region. The guard rings respectively comprise a first portion adjacent the surface and a second portion spaced from the surface, where the first portion is wider than the second portion. Related devices and fabrication methods are also discussed.

Edge termination for power semiconductor devices and related fabrication methods

A semiconductor device includes a vertical transistor and a body diode. Various improvements to the semiconductor device allow for improved performance of the body diode, in particular to reduced snappiness and increased softness.

Power transistor with soft recovery body diode

A power metal-oxide-semiconductor field-effect transistor (MOSFET) includes a substrate, a drift layer over the substrate, and a spreading layer over the drift layer. The spreading layer includes a pair of junction implants separated by a junction gate field effect (JFET) region. A gate oxide layer is on top of the spreading layer. The gate contact is on top of the gate oxide layer. Each one of the source contacts are on a portion of the spreading layer separate from the gate oxide layer and the gate contact. The drain contact is on the surface of the substrate opposite the drift layer.

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Raleigh, NC, United States of America

Daniel Jenner Lichtenwalner