Crystal layered structure and method for manufacturing same, and semiconductor element

A method for manufacturing a crystal layered structure, comprising:

• a step of forming a buffer layer by growing a first AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on a Ga2O3 substrate;
• and
• a step of forming a nitride semiconductor layer by growing a second AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on the buffer layer,
• wherein the second AlxGayInzN crystal is initially grown at a first temperature of not more than 1000° C. and is then grown at a second temperature higher than the first temperature in the step of forming the nitride semiconductor layer, and
• wherein the second AlxGayInzN crystal grown at the first temperature is not less than 200 nm in thickness.

A crystal layered structure, comprising:

• a Ga2O3 substrate;
• a buffer layer comprising an AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on the Ga2O3 substrate;
• and
• a nitride semiconductor layer comprising an AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on the buffer layer,
• wherein a percentage of a surface of the Ga2O3 substrate covered with the buffer layer in a region immediately below the nitride semiconductor layer is not less than 10% and less than 100%, and
• wherein a portion of the nitride semiconductor layer is in contact with the surface of the Ga2O3 substrate.

A method for manufacturing a crystal layered structure, comprising:

• a step of forming a buffer layer by growing a first AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on a Ga2O3 substrate so as to partially cover a surface of the Ga2O3 substrate;
• and
• a step of foaming a nitride semiconductor layer by growing a second AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on the buffer layer,
• wherein a percentage of a surface of the Ga2O3 substrate covered with the buffer layer in a region immediately below the nitride semiconductor layer is not less than 10% and less than 100%, and
• wherein a portion of the nitride semiconductor layer is in contact with the surface of the Ga2O3 substrate.

A method for manufacturing a crystal layered structure, comprising:

• a step of forming a buffer layer by growing a first AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal at a first temperature on a Ga2O3 substrate of which principal surface is a surface having an oxygen atom arranged in a hexagonal lattice pattern;
• and
• a step of forming a nitride semiconductor layer by growing a second AlxGayInzN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) crystal on the buffer layer,
• wherein a step of nitriding a surface of the Ga2O3 substrate at a higher temperature than the first temperature is not performed before forming the buffer layer.