University of California

Xun Zheng

Umesh Kumar Mishra

Stacia Keller

Brian Romanczyk

Matthew Guidry

Elaheh Ahmadi

Haoran Li

Steven Wienecke

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.

III-N transistor structures with stepped cap layers

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 (InGaN) and indium composition (In) was investigated for different channel thicknesses. With optimizedInGaN andIn, significant improvements in electron mobility were observed. For a 6 nm channel HEMT, the electron mobility increased from 606 to 1141 cm/(V&#xb7;s) when the 6 nm thick pure GaN channel was replaced by the 4 nm GaN/2 nm InGaN composite channel.

Structure for increasing mobility in a high electron mobility transistor

Growing community of inventors

Santa Barbara, CA, United States of America

Xun Zheng