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) (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) BARREIER LAYER (30) IS ON THE ALyGa1-yN LAYER (28), OPPOSITE THE GAN BUFFER LAYER (26), THE ALyGa1-yN LAYER (28) HAVING A HIGHER A1 CONCENTRATION THAN THAT OF THE ALxGa1-xN BARRIER LAYER (30). A PREFERRED ALygA1-yN LAYER (28) HAS Y=1 OR Y~1 AND A PREFERRED ALxGa1-xN BARRIER LAYER (30) HAS 0,x,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 ALYER (28) AND A NUCLEATION LAYER (24) CAN BE INCLUDED BETWEEN THE GAN BUFFER LAYER (26) AND THE SUBSTRATE (22). (FIG. 2)