Crystal, semiconductor element and semiconductor device

A multilayer structure comprising:

• a semiconductor layer including a dopant and a corundum structured crystalline oxide semiconductor as a major component, the corundum structured crystalline oxide semiconductor containing a first metal that is gallium and/or indium;
• a crystal film on the semiconductor layer, the crystal film including a corundum structured crystalline oxide, the corundum structured crystalline oxide containing a second metal of Group 4 of the periodic table and a third metal that is gallium and/or indium;
• and
• a metal layer on the crystal film, the metal layer including a fourth metal of Group 4 of the periodic table as a major component, wherein
• a composition ratio of the second metal to the second and third metals contained in the crystal film is greater than a composition ratio of the dopant to the semiconductor layer.