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Group-III nitride based high electron mobility transistor (HEMT) with barrier/spacer layer

United States Patent

6,849,882
February 1, 2005
View the Complete Patent at the US Patent & Trademark Office
Lawrence Berkeley National Laboratory - Visit the Technology Transfer and Intellectual Property Management Department Website
A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an Al.sub.y Ga.sub.1-y N (y=1 or y 1) layer on the GaN buffer layer. An Al.sub.x Ga.sub.1-x N (0.ltoreq.x.ltoreq.0.5) barrier layer on to the Al.sub.y Ga.sub.1-y N layer, opposite the GaN buffer layer, Al.sub.y Ga.sub.1-y N layer having a higher Al concentration than that of the Al.sub.x Ga.sub.1-x N barrier layer. A preferred Al.sub.y Ga.sub.1-y N layer has y=1 or y.about.1 and a preferred Al.sub.x Ga.sub.1-x N barrier layer has 0.ltoreq.x.ltoreq.0.5. A 2DEG forms at the interface between the GaN buffer layer and the Al.sub.y Ga.sub.1-y N layer. Respective source, drain and gate contacts are formed on the Al.sub.x Ga.sub.1-x N barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the Al.sub.y Ga.sub.1-y N layer and a nucleation layer between the Al.sub.x Ga.sub.1-x N buffer layer and the substrate.
Chavarkar; Prashant (Goleta, CA), Smorchkova; Ioulia P. (Redondo Beach, CA), Keller; Stacia (Santa Barbara, CA), Mishra; Umesh (Santa Barbara, CA), Walukiewicz; Wladyslaw (Kensington, CA), Wu; Yifeng (Goleta, CA)
Cree Inc. (Goleta, CA)
10/ 102,272
March 19, 2002
This invention was made with Government support under Contract Nos. N00014-96-1-1215 and N00014-99-1-0729, awarded by the ONR and Contract No. F49620-00-1-0143 awarded by AFOSR. The Government has certain rights in this invention. This invention was made with Government support under Contract No. DE-AC03-76SF00098 awarded by the Director Office of Energy Research, Office of Science, Division of Materials Sciences of the U.S. Department of Energy. This invention was made with Government support under Contract No. N00014-00-C-0004, awarded by the ONR. The Government has certain rights in this invention.