Semiconductor laminate, semiconductor device, and method for manufacturing semiconductor device

A semiconductor laminate at least comprising:

• a base;
• a buffer layer;
• and
• a crystalline metal oxide semiconductor film containing at least one metal element and having a corundum structure, the semiconductor laminate having the buffer layer on a main surface of the base directly or via another layer, the semiconductor laminate having the crystalline metal oxide semiconductor film on the buffer layer, wherein
• the buffer layer is a laminate structure of a plurality of buffer films each with a different composition, and
• all of the plurality of buffer films have a film thickness of 200 nm or more and 650 nm or less, wherein
• the buffer films contain a main metal element of the crystalline metal oxide semiconductor film that is the most abundant among metal elements contained in the crystalline metal oxide semiconductor film, and
• the buffer layer is a laminate structure in which the plurality of buffer films are laminated such that a proportion of the main metal element of the crystalline metal oxide semiconductor film increases from the base side toward the crystalline metal oxide semiconductor film side of the buffer layer.

A method for manufacturing a semiconductor device at least including a crystalline metal oxide semiconductor film and an electrode, comprising:

• a step of forming a plurality of buffer films, each with a different composition, as a buffer layer on a main surface of a base, the plurality of buffer films including two or more buffer films with a thickness of 200 nm or more and 650 nm or less, wherein
• the buffer films contain a main metal element of the crystalline metal oxide semiconductor film that is the most abundant among metal elements contained in the crystalline metal oxide semiconductor film, and
• the buffer layer is a laminate structure in which the plurality of buffer films are laminated such that a proportion of the main metal element of the crystalline metal oxide semiconductor film increases from the base side toward the crystalline metal oxide semiconductor film side of the buffer layer;
• a step of forming a crystalline metal oxide semiconductor film with a corundum structure on the buffer layer;
• and
• a step of forming an electrode at least on the crystalline metal oxide semiconductor film.

A method for manufacturing a semiconductor device at least including a crystalline metal oxide semiconductor film and an electrode, comprising:

• a step of forming a plurality of buffer films, each with a different composition and a thickness of 200 nm or more and 650 nm or less, as a buffer layer on a main surface of a base, wherein
• the buffer films contain a main metal element of the crystalline metal oxide semiconductor film that is the most abundant among metal elements contained in the crystalline metal oxide semiconductor film, and
• the buffer layer is a laminate structure in which the plurality of buffer films are laminated such that a proportion of the main metal element of the crystalline metal oxide semiconductor film increases from the base side toward the crystalline metal oxide semiconductor film side of the buffer layer;
• a step of forming a crystalline metal oxide semiconductor film with a corundum structure on the buffer layer;
• and
• a step of forming an electrode at least on the crystalline metal oxide semiconductor film.