Silicon carbide substrate, silicon carbide semiconductor device, method for manufacturing silicon carbide substrate, and method for manufacturing silicon carbide semiconductor device

A silicon carbide semiconductor device, comprising:

• a single crystal substrate made of silicon carbide and having a first front-side surface and a first backside surface opposite to each other;
• a support substrate having a second front-side surface and a second backside surface opposite to each other;
• a connection layer having silicon carbide as a main component and lying between said single crystal substrate and said support substrate for connecting said first backside surface and said second front-side surface such that said first backside surface faces said second front-side surface;
• an epitaxial layer provided on said first front-side surface of said single crystal substrate and made of silicon carbide;
• and
• an electrode provided on said epitaxial layer.

A method for manufacturing a silicon carbide substrate, comprising the steps of:

• preparing a plurality of single crystal substrates and a support substrate, said plurality of single crystal substrates being made of silicon carbide and each having a first front-side surface and a first backside surface opposite to each other, said support substrate having a second front-side surface and a second backside surface opposite to each other;
• arranging each of said plurality of single crystal substrates on said support substrate with a fluid layer containing polycarbosilane interposed therebetween, such that each of said first backside surfaces of said plurality of single crystal substrates faces said second front-side surface of said support substrate;
• and
• forming a connection layer having silicon carbide as a main component by converting said polycarbosilane.

A method for manufacturing a silicon carbide semiconductor device, comprising the steps of:

• preparing a silicon carbide substrate including a single crystal substrate, a support substrate, and a connection layer, said single crystal substrate being made of silicon carbide and having a first front-side surface and a first backside surface opposite to each other, said support substrate having a second front-side surface and a second backside surface opposite to each other, said connection layer having silicon carbide as a main component and lying between said single crystal substrate and said support substrate for connecting said first backside surface and said second front-side surface such that said first backside surface faces said second front-side surface;
• forming an epitaxial layer on said single crystal substrate;
• and
• forming an electrode on said epitaxial layer.