Hafnium nitride buffer layers for growth of GaN on silicon

Abstract

Gallium nitride is grown by plasma-assisted molecular-beam epitaxy on (111) and (001) silicon substrates using hafnium nitride buffer layers. Wurtzite GaN epitaxial layers are obtained on both the (111) and (001) HfN/Si surfaces, with crack-free thickness up to 1.2 Om. However, growth on the (001) surface results in nearly stress-free films, suggesting that much thicker crack-free layers could be obtained.

1 - 9 . (canceled)  
     
     
         10 . A composite wafer, comprising: 
 a substrate comprising Si,    a buffer layer comprising HfN (001) overlying said Si substrate, and    a GaN layer on said buffer layer.    
     
     
         11 . The composite wafer as claimed in  claim 10 , wherein: 
 there is more than one buffer layer comprising HfN.    
     
     
         12 . The composite wafer as claimed in  claim 11 , wherein: 
 there are two buffer layers comprising HfN overlying said Si substrate.    
     
     
         13 . The composite wafer as claimed in  claim 10 , wherein: 
 the buffer layer overlies directly on the Si substrate.    
     
     
         14 . The composite wafer as claimed in  claim 10 , wherein: 
 the substrate comprises Si (001).    
     
     
         15 . The composite wafer as claimed in  claim 14 , wherein: 
 the GaN layer comprises wurtzite GaN.    
     
     
         16 . The composite wafer as claimed in  claim 14 , wherein: 
 the HfN(001) layer lies directly on the Si(001) layer.