公开(公告)号：US20200273974A1

公开(公告)日：2020-08-27

申请号：US16802388

申请日：2020-02-26

Applicant: The Regents of the University of California

Inventor： Matthew Guidry ,  Stacia Keller ,  Umesh K. Mishra ,  Brian Romanczyk ,  Xun Zheng

IPC: H01L29/778 ,  H01L29/20 ,  H01L29/66

Abstract: Described herein are III-N (e.g. GaN) devices having a stepped cap layer over the channel of the device, for which the III-N material is orientated in an N-polar orientation.

公开(公告)号：US11594625B2

公开(公告)日：2023-02-28

申请号：US16802388

申请日：2020-02-26

Applicant: The Regents of the University of California

Inventor： Matthew Guidry ,  Stacia Keller ,  Umesh K. Mishra ,  Brian Romanczyk ,  Xun Zheng

IPC: H01L29/778 ,  H01L29/20 ,  H01L29/66

Abstract: Described herein are III-N (e.g. GaN) devices having a stepped cap layer over the channel of the device, for which the III-N material is orientated in an N-polar orientation.

公开(公告)号：US20210399121A1

公开(公告)日：2021-12-23

申请号：US17353665

申请日：2021-06-21

Applicant: The Regents of the University of California

Inventor： Brian Romanczyk ,  Umesh K. Mishra ,  Pawana Shrestha ,  Matthew Guidry ,  James Buckwalter ,  Stacia Keller ,  Rohit Reddy Karnaty

IPC: H01L29/778 ,  H01L29/10 ,  H01L29/205 ,  H01L29/423 ,  H01L29/66 ,  H01L29/267

Abstract: Derivative cancellation techniques have been used to linearize transistors using multiple discreet devices. However at frequencies approaching and in the mm-wave regime the use of individual devices no longer works due to the parasitics associated with combining the devices. In this invention device structures are described which apply the derivative cancellation technique in a single device thus removing the detrimental impact of combining. In one example, an N-polar transistor structure includes a channel; a cap structure comprising a plurality of cap layers on or above the channel; a source contact and a drain contact to the channel; and a castellated, stepped, or varying pattern formed in the cap layers so that gate metal deposited on the pattern forms at least two different threshold voltages and current combines in the ohmic region with essentially zero parasitic inductance.

公开(公告)号：US11101379B2

公开(公告)日：2021-08-24

申请号：US16461505

申请日：2017-11-16

Applicant: The Regents of the University of California

Inventor： Brian Romanczyk ,  Haoran Li ,  Elaheh Ahmadi ,  Steven Wienecke ,  Matthew Guidry ,  Xun Zheng ,  Stacia Keller ,  Umesh K. Mishra

IPC: H01L29/66 ,  H01L29/778 ,  H01L29/10 ,  H01L29/20 ,  H01L29/205

Abstract: A novel design for a nitrogen polar high-electron-mobility transistor (HEMT) structure comprising a GaN/InGaN composite channel. As A novel design for a nitrogen polar high-electron-mobility transistor (HEMT) structure comprising a GaN/InGaN composite channel. As illustrated herein, a thin InGaN layer introduced in the channel increases the carrier density, reduces the electric field in the channel, and increases the carrier mobility. The dependence of p on InGaN thickness (tInGaN) and indium composition (xIn) was investigated for different channel thicknesses. With optimized tInGaN and xIn, significant improvements in electron mobility were observed. For a 6 nm channel HEMT, the electron mobility increased from 606 to 1141 cm2/(V·s) when the 6 nm thick pure GaN channel was replaced by the 4 nm GaN/2 nm In0.1Ga0.9N composite channel.