Method of manufacturing GaN substrate, method of manufacturing epitaxialwafer, method of manufacturing semiconductor device and epitaxialwafer

摘要

Assuming that r (m) represents the radius of a GaN substrate, t1 (m) represents the thickness of the GaN substrate, h1 (m) represents a warp of the GaN substrate before formation of an epitaxialwafer, t2 (m) represents the thickness of an AlxGa(1-X)N layer, h2 (m) represents a warp of the epitaxialwafer, a1 represents the lattice constant of GaN and a2 represents the lattice constant of AlN, the value t1 found by the following expression is decided as the minimum thickness (t1) of the GaN substrate: (1.5×1011×t13+1.2×1011×t23)×{1/(1.5×1011×t1)+1/(1.2×1011×t2)}/{15.96×x×(1-a2/a1)}×(t1+t2)+(t1×t2)/{5.32×x×(1-a2/a1)}-(r2+h2)/2h=0 A GaN substrate having a thickness of at least this minimum thickness (t1) and less than 400 mum is formed.