Semiconductor device and manufacturing method of semiconductor device
A manufacturing method of a semiconductor device includes: forming an electric metal layer by depositing metal as art electrode material on an inside of an opening of an insulating layer on a surface of an SiC semiconductor substrate; widening a gap between an inner wall surface in an opening formed in the insulating layer and the electrode metal layer by etching the insulating layer after the electrode metal layer is formed; and forming an ohmic contact between the electrode metal layer and the SiC semiconductor substrate by heating the SiC semiconductor substrate and the metal electrode layer after the insulating layer is etched.
1. A manufacturing method of a semiconductor device, the method comprising:
forming an insulating layer on a surface of a silicon carbide semiconductor substrate;
forming a resist layer having an opening on a surface of the insulating layer;
removing the insulating layer in an area exposed through the opening of the resist layer;
forming an electrode metal layer by depositing metal as an electrode material on the surface of the SiC semiconductor substrate and a surface of the resist layer in a state where the resist layer is formed on the insulating layer after the insulating layer is removed;
removing the resist layer on which the electrode metal layer is deposited after the electrode metal layer is formed;
widening a gap between an inner wall surface of an opening formed in the insulating layer and the electrode metal layer by etching after the resist layer is removed; and
forming an ohmic contact between the electrode metal layer and the SiC semiconductor substrate by heating the SiC semiconductor substrate and the electrode metal layer after the etching is performed, wherein
the forming the electrode metal layer includes:
forming an ohmic electrode layer by depositing a metal material which forms an ohmic contact with the SiC semiconductor substrate on the surface of the SiC semiconductor substrate and the surface of the resist layer; and
forming a protective metal layer by depositing a metal material which protects the ohmic electrode layer on a face side of the ohmic electrode layer after the ohmic electrode layer is formed,
wherein in the etching of the insulating layer, side walls of the ohmic electrode layer are etched, the protective metal layer is not etched, and the heating is performed at a temperature not lower than a melting point of the protective metal layer.
2. The method of a semiconductor device according to claim 1 , wherein the etching is wet etching which uses an etching solution, and
wherein an etching rate of the etching solution for the protective metal layer is lower than an etching rate of the etching solution for the insulating layer and lower than an etching rate of the etching solution for the ohmic electrode layer.
3. The method of a semiconductor device according to claim 2 , further comprising forming a carbon adsorbing metal layer by depositing a metal material which adsorbs carbon on a surface of the ohmic electrode layer between the forming the ohmic electrode layer and the forming the protective metal layer.