Epitaxial substrate for electronic device and method of producing the same

Abstract

An object of the present invention is to provide an epitaxial substrate for an electronic device, in which a lateral direction of the substrate is defined as a main current conducting direction and a warp configuration of the epitaxial substrate is adequately controlled, as well as a method of producing the epitaxial substrate. Specifically, the epitaxial substrate for an electron device, including: a Si single crystal substrate; and a Group III nitride laminated body formed by epitaxially growing plural Group III nitride layers on the Si single crystal substrate, wherein a lateral direction of the epitaxial substrate is defined as a main current conducting direction, is characterized in that the Si single crystal substrate is a p-type substrate having a specific resistance value of not larger than 0.01 Ω·cm.

1 . An epitaxial substrate for an electronic device, including: a Si single crystal substrate; and a Group III nitride laminated body formed by epitaxially growing plural Group III nitride layers on the Si single crystal substrate, wherein a lateral direction of the epitaxial substrate is defined as a main current conducting direction, wherein:
 the Si single crystal substrate is a p-type substrate having a specific resistance value of not larger than 0.01 Ω·cm.   
     
     
         2 . The epitaxial substrate for an electronic device of  claim 1 , wherein a sectional warp configuration of the epitaxial substrate satisfies a relationship formula below.
   ∥ Bow|−SORI|≦ 2 μm
   
     
     
         3 . The epitaxial substrate for an electronic device of  claim 1 , wherein a sectional warp configuration of the epitaxial substrate is monotonously bowed over the entire width of the epitaxial substrate. 
     
     
         4 . The epitaxial substrate for an electronic device of  claim 1 , wherein the Si single crystal substrate contains as an impurity element boron at a concentration of 10 19 /cm 3  or higher. 
     
     
         5 . The epitaxial substrate for an electronic device of  claim 1 , further comprising a buffer as an insulating layer between the Si single crystal substrate and the Group III nitride laminated body. 
     
     
         6 . The epitaxial substrate for an electronic device of  claim 5 , wherein the buffer includes a lamination constituted of a superlattice multilayer structure. 
     
     
         7 . A method of producing an epitaxial substrate for an electronic device, in which a Group III nitride laminated body is formed by epitaxially growing plural Group III nitride layers on a Si single crystal substrate such that a lateral direction of the substrate is defined as a main current conducting direction, comprising:
 forming the Si single crystal substrate to be a p-type substrate having a specific resistance value of not larger than 0.01 Ω·cm by adding boron thereto at a relatively high concentration.   
     
     
         8 . The method of producing an epitaxial substrate for an electronic device of  claim 7 , wherein boron is added at a concentration of 10 19 /cm 3  or higher. 
     
     
         9 . The method of producing an epitaxial substrate for an electronic device of  claim 7 , further comprising:
 forming on the Si single crystal substrate a buffer as an insulating layer including a lamination constituted of a superlattice multilayer structure, prior to formation of the Group III nitride laminated body; and   forming the Group III nitride laminated body having a HEMT structure on the buffer.