High electron mobility transistor and method for fabricating the same

Abstract

A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a first barrier layer on a substrate; forming a p-type semiconductor layer on the first barrier layer; forming a hard mask on the p-type semiconductor layer; patterning the hard mask and the p-type semiconductor layer; and forming a spacer adjacent to the hard mask and the p-type semiconductor layer.

What is claimed is: 
     
         1 . A method for fabricating high electron mobility transistor (HEMT), comprising:
 forming a first barrier layer on a substrate;   forming a p-type semiconductor layer on the first barrier layer;   forming a hard mask on the p-type semiconductor layer;   patterning the hard mask and the p-type semiconductor layer; and   forming a spacer adjacent to the hard mask and the p-type semiconductor layer.   
     
     
         2 . The method of  claim 1 , further comprising forming a buffer layer on the substrate before forming the first barrier layer. 
     
     
         3 . The method of  claim 1 , further comprising:
 forming a second barrier layer on the first barrier layer adjacent to the spacer;   forming a gate electrode on the hard mask; and   forming a source electrode and a drain electrode adjacent to two sides of the spacer.   
     
     
         4 . The method of  claim 3 , wherein the hard mask comprises a conductive material. 
     
     
         5 . The method of  claim 1 , further comprising:
 forming a second barrier layer on the first barrier layer adjacent to the spacer;   forming a gate electrode in the hard mask and on the p-type semiconductor layer; and   forming a source electrode and a drain electrode adjacent to two sides of the spacer.   
     
     
         6 . The method of  claim 5 , wherein the hard mask comprises a dielectric material. 
     
     
         7 . The method of  claim 1 , wherein the first barrier layer comprise Al x Ga 1-x N. 
     
     
         8 . A method for fabricating high electron mobility transistor (HEMT), comprising:
 forming a first barrier layer on a substrate;   forming a p-type semiconductor layer on the first barrier layer;   patterning the p-type semiconductor layer; and   forming a spacer adjacent to the p-type semiconductor layer.   
     
     
         9 . The method of  claim 8 , further comprising forming a buffer layer on the substrate before forming the first barrier layer. 
     
     
         10 . The method of  claim 8 , further comprising:
 forming a second barrier layer on the p-type semiconductor layer and the first barrier layer adjacent to the spacer;   forming a hard mask on the second barrier layer;   planarizing the hard mask;   forming a gate electrode on the p-type semiconductor layer; and   forming a source electrode and a drain electrode adjacent to two sides of the spacer.   
     
     
         11 . The method of  claim 10 , further comprising planarizing the hard mask and the second barrier layer so that top surfaces of the hard mask and the p-type semiconductor layer are coplanar. 
     
     
         12 . The method of  claim 8 , wherein the first barrier layer comprise Al x Ga 1-x N.