摘要 |
An object of the present invention is to provide an epitaxial substrate for an electronic device capable of making decrease in lateral leakage current and achievement of good properties of withstand voltage in a lateral direction compatible and enhancing withstand voltage in the vertical direction, as well as a method of producing said epitaxial substrate. Specifically, the present invention provides an epitaxial substrate for an electronic device having a Si single crystal substrate, a buffer as an insulating layer formed on the Si single crystal substrate, and a main laminated body formed by plural group III nitride layers epitaxially grown on the buffer, wherein a lateral direction of the epitaxial substrate is defined as an electric current conducting direction, characterized in that : the buffer includes at least an initially grown layer in contact with the Si single crystal substrate and a superlattice laminate constituted of a superlattice multilayer structure on the initially grown layer; the initially grown layer is made of an AlN material; the superlattice laminate is formed by alternate lamination of a first layer made of a Ba 1 Al b1 Ga c1 In d1 N (0 ‰¤ a 1 ‰¤ 1, 0 ‰¤ b 1 ‰¤ 1, 0 ‰¤ c 1 ‰¤ 1, 0 ‰¤ d 1 ‰¤ 1, a 1 + b 1 + c 1 + d 1 = 1) material and a second layer made of a B a2 Al b2 Ga c2 In d2 N (0 ‰¤ a 2 ‰¤ 1, 0 ‰¤ b 2 ‰¤ 1, 0 ‰¤ c 2 ‰¤ 1, 0 ‰¤ d 2 ‰¤ 1, a 2 + b 2 + c 2 + d 2 = 1) material having a band gap different from that of the first layer; and both of the superlattice laminate and a portion, on the buffer side, of the main laminated body has carbon concentration of 1 × 10 18 /cm 3 or higher. |