ZnO group epitaxial semiconductor device and its manufacture

Abstract

A method for manufacturing a semiconductor device includes the steps of: (a) preparing a non-polar single crystal substrate; (b) epitaxially growing an MgO layer on the non-polar single crystal substrate to a thickness of 3 nm or thicker to have rocksalt structure at a substrate temperature of 500° C. to 800° C.; (c) growing on the MgO layer a low temperature growth layer made of ZnO group material at a substrate temperature of 500° C. or lower; (d) annealing the low temperature growth layer above the substrate at a temperature of 700° C. or higher; and (e) epitaxially growing a high temperature growth layer of ZnO group material on the annealed low temperature growth layer at a temperature of 600° C. or higher.

1 - 11 . (canceled)  
   
   
       12 . A method for manufacturing a semiconductor device comprising the steps of: 
 (a) preparing an underlying layer having a single crystal surface;    (b) epitaxially growing an MgO layer above said underlying layer to a thickness which enables, when a ZnO layer is grown thereon, to provide a +c polarity; and    (c) growing on said MgO layer a layer consisting essentially of ZnO.    
   
   
       13 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said step (b) grows said MgO layer having rocksalt structure.  
   
   
       14 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said step (b) epitaxially grows said MgO layer to a thickness of 3 nm or thicker.  
   
   
       15 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said underlying layer is a non-polar single crystal substrate.  
   
   
       16 . The method for manufacturing a semiconductor device according to  claim 15 , wherein said non-polar single crystal substrate is a sapphire substrate, an ScAlMgO 4  substrate or an Si substrate.  
   
   
       17 . The method for manufacturing a semiconductor device according to  claim 15  wherein said non-polar single crystal substrate is a c-plane sapphire substrate.  
   
   
       18 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said underlying layer is a −c polarity ZnO layer.  
   
   
       19 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said step (c) comprises the steps of: 
 (c-1) growing on said MgO layer a low temperature grown layer consisting essentially of ZnO, at a substrate temperature of 500° C. or lower;    (c-2) annealing said low temperature growth layer at a temperature of 700° C. or higher; and    (c-3) epitaxially growing on said annealed low temperature grown layer a high temperature grown layer consisting essentially of ZnO, at a substrate temperature of 600° C. or higher.    
   
   
       20 . The manufacture method for a semiconductor device according to  claim 12 , wherein said step (b) is performed at a substrate temperature of 500° C. to 800° C.  
   
   
       21 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said steps (b) and (c) are performed by molecular beam epitaxy (MBE).  
   
   
       22 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said step (c) includes a step of growing a p-type layer doped with nitrogen.