Group III nitride semiconductor epitaxial substrate and method for manufacturing the same

A method for manufacturing a group III nitride semiconductor epitaxial substrate comprising:

• a step for forming a mask pattern composed of carbon directly on top of a sapphire substrate for growing an epitaxial film;
• and
• a step for forming an ELO layer having a composition of AlxGa1-xN (0≦x≦1) by using the mask pattern, while preventing the formation of polycrystalline growth on the mask pattern, such that the mask pattern reacts under a high temperature ranging from 1250° C. to 1400° C. with H2 serving as a carrier gas or an ammonium NH3 contained in the raw material as nitrogen source to be eliminated, such that the carbon base mask may be completely eliminated between the substrate and the ELO layer.

A method for manufacturing a group III nitride semiconductor epitaxial substrate comprising:

• a step for forming a mask pattern composed of carbon directly on top of a sapphire substrate for growing an epitaxial film;
• and
• a step for forming an ELO layer having a composition of AlxGa1-xN (0<x≦1) by using the mask pattern, while preventing the formation of polycrystalline growth on the mask pattern, such that the mask pattern reacts under a high temperature ranging from 1250° C. to 1400° C. with H2 serving as a carrier gas or an ammonium NH3 contained in the raw material as a nitrogen source to be eliminated, such that the carbon base mask may be present between the substrate and the ELO layer.