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

摘要

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.