GROUP-III NITRIDE BASED HIGH ELECTRON MOBILITY TRANSISTOR (HEMT) WITH BARRIER/SPACER LAYER

摘要

A group III nitride based high electron mobility transistor (HEMT) (10) is disclosed that provides improved high frequency performance. One embodiment of the HEMT (10) comprises a GaN buffer layer (26), with an AlyGa1-yN (y=1 or y 1) layer (28) on the Gan buffer layer (26). An AlxGa1-xN (0<=x<=0.5) b arrier layer (30) is on the AlyGa1-yN layer (28), opposite the GaN buffer layer (26 ), the AlyGa1-yN layer (28) having a higher Al concentration than that of the AlxGa1-xN barrirer layer (30). A preferred AlyGa1-yN layer (28) has y=1 or y.congruent.1 and a preferred AlxGa1-xN barrier layer (30) has 0<=0.5. A 2DEG (38) forms at the interface between the GaN buffer layer (26) and the AlyGa1 - yN layer (28). Respective source, drain and gate contacts (32, 34, 36) are formed on the AlxGa1-xN barrier layer (30). The HEMT (10) can also include a substrate (22) adjacent to the buffer layer (26), opposite the AlyGa1-yN lay er (28) and a nucleation layer (24) can be included between the GaN buffer laye r (26) and the substrate (22).