Abstract: A Ga2O3 semiconductor element includes: an n-type ?-Ga2O3 single crystal film, which is formed on a high-resistance ?-Ga2O3 substrate directly or with other layer therebetween; a source electrode and a drain electrode, which are formed on the n-type ?-Ga2O3 single crystal film; and a gate electrode, which is formed on the n-type ?-Ga2O3 single crystal film between the source electrode and the drain electrode.

Abstract: Provided is a high-quality Ga2O3 semiconductor element. Provided is, as one embodiment of the present invention, a Ga2O3 MESFET (10), which includes: an n-type ?-(AlxGa1-x)2O3 single crystal film (3), which is formed on an ?-Al2O3 substrate (2) directly or with other layer therebetween, and is composed of an ?-(AlxGa1-x)2O3 single crystal (0?x?1); a source electrode (12) and a drain electrode (13), which are formed on the n-type ?-(AlxGa1-x)2O3 single crystal film (3); and a gate electrode (11), which is formed on a region between the source electrode (12) and the drain electrode (13) on the n-type ?-(AlxGa1-x)2O3 single crystal film (3).

Abstract: A crystal laminate structure, in which crystals can be epitaxially grown on a ?-Ga2O3-based substrate with high efficiency to produce a high-quality ?-Ga2O3-based crystal film on the substrate; and a method for producing the crystal laminate structure are provided. The crystal laminate structure includes: a ?-Ga2O3-based substrate, of which the major face is a face that is rotated by 50 to 90° inclusive with respect to face; and a ?-Ga2O3-based crystal film which is formed by the epitaxial crystal growth on the major face of the ?-Ga2O3-based substrate.