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

US6849882B2 · kind B2 · utility

Assignee

• Cree, Inc. · US

Inventors

• Prashant Chavarkar · Goleta, US
• Ioulia Smorchkova · Lakewood, US
• Stacia Keller · Midland School, US
• Umesh Mishra · Montecito, US
• Wladyslaw Walukiewicz · Kensington, US
• Yifeng Wu · Goleta, US

Key dates

• Filing date: Mar 19, 2002
• Grant date: Feb 1, 2005
• Expiry date: May 17, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/8503

Abstract

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 AlyGa1−yN (y=1 or y 1) layer on the GaN buffer layer. An AlxGa1−xN (0≦x≦0.5) barrier layer on to the AlyGa1−yN layer, opposite the GaN buffer layer, AlyGa1−yN layer having a higher Al concentration than that of the AlxGa1−xN barrier layer. A preferred AlyGa1−yN layer has y=1 or y˜1 and a preferred AlxGa1−xN barrier layer has 0≦x≦0.5. A 2DEG forms at the interface between the GaN buffer layer and the AlyGa1−yN layer. Respective source, drain and gate contacts are formed on the AlxGa1−xN barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the AlyGa1−yN layer and a nucleation layer between the AlxGa1−xN buffer layer and the substrate.