A process for manufacturing a silicon carbide device from a body of silicon carbide having a back surface, wherein a first layer of a first metal is formed on the back surface of the body; a second layer of a second metal, different from the first metal, is formed on the first layer to form a multilayer, the first or the second metal being nickel or a nickel alloy and forming a nickel-based layer, another of the first or the second metal being a metal X, capable to form stable compounds with carbon and forming an X-based layer; and the multilayer is annealed to form a mixed layer including nickel silicide and at least one of X carbide or a metal X-carbon ternary compound.

A method for manufacturing a group III nitride semiconductor substrate, that includes: growing a first AlN buffer layer on an Si substrate at a first growth temperature; growing a second AlN buffer layer on the first AlN buffer layer at a second growth temperature higher than the first growth temperature; and growing a group III nitride semiconductor layer on the second AlN buffer layer, wherein an Al raw material and an N raw material are alternately repeatedly fed in the growing the first AlN buffer layer.

A method for manufacturing an epitaxial substrate includes the steps of: epitaxially growing a group III nitride semiconductor layer on a substrate; removing the substrate from a growth furnace; irradiating a surface of the group III nitride semiconductor layer with ultraviolet light while exposing the surface to an atmosphere containing oxygen; and measuring a sheet resistance value of the group III nitride semiconductor layer.

A substrate processing method of processing a substrate having a base film includes a loading process of loading the substrate into a processing container, a first process of performing a first plasma process in a state where the loaded substrate is held at a first position by raising substrate support pins of a stage arranged in the processing container, and a second process of performing a second plasma process while holding the substrate at a second position by lowering the substrate support pins.