CRYSTAL, CRYSTALLINE FILM, SEMICONDUCTOR DEVICE INCLUDING CRYSTALLINE FILM, AND METHOD FOR PRODUCING CRYSTALLINE FILM
According to an aspect of a present inventive subject matter, a crystal includes: a corundum-structured oxide semiconductor as a major component, the corundum-structured oxide semiconductor including gallium and/or indium and doped with a dopant including germanium; a principal plane; a carrier concentration that is 1×10 18 /cm 3 or more; and an electron mobility that is 20 cm 2 /Vs or more.
1 . A crystal comprising:
a corundum-structured oxide semiconductor as a major component, the corundum-structured oxide semiconductor comprising gallium and/or indium and doped with a dopant comprising germanium;
a principal plane;
a carrier concentration that is 1×10 18 /cm 3 or more; and
an electron mobility that is 20 cm 2 /Vs or more.
2 . The crystal of claim 1 , wherein
the principal plane of the crystal is a c-plane.
3 . The crystal of claim 1 , wherein
the principal plane of the crystal is an m-plane.
4 . The crystal of claim 1 , wherein
the principal plane of the crystal comprises an off-angle.
5 . The crystal of claim 1 , wherein
the corundum-structured oxide semiconductor comprises a mixed crystal comprising gallium and one or more metals selected from among aluminum, indium, iron, chromium, vanadium, titanium, rhodium, nickel, cobalt, and iridium.
6 . The crystal of claim 1 , wherein
the crystal has a film shape as a crystalline film.
7 . The crystal of claim 5 , wherein the mixed crystal comprised in the corundum-structured oxide semiconductor comprises aluminum that is 1×10 17 /cm 3 or more.
8 . A crystalline film comprising:
an oxide semiconductor as a major component, the oxide semiconductor comprising aluminum that is 1×10 17 /cm 3 or more;
a carrier concentration that is 1×10 18 /cm 3 or more; and
an electron mobility that is 20 cm 2 /Vs or more.
9 . The crystalline film of claim 8 , wherein
the oxide semiconductor comprises gallium.
10 . The crystalline film of claim 8 , wherein
the oxide semiconductor comprises a mixed crystal.
11 . A semiconductor device comprising:
the crystal of claim 6 ;
a first electrode electrically connected to the crystal; and
a second electrode electrically connected to the crystal.
12 . A semiconductor device comprising:
a crystalline film of claim 8 ;
a first electrode electrically connected to the crystalline film; and
a second electrode electrically connected to the crystalline film.
13 . A method for producing a crystalline film comprising:
gasifying a metal source to turn the metal source into a metal-containing raw-material gas;
supplying the metal-containing raw-material gas, an oxygen-containing raw-material gas into a reaction chamber onto a substrate;
supplying a dopant-containing raw-material gas and a reactive gas into the reaction chamber onto the substrate; and
forming a crystalline film under gas flow of the dopant-containing raw-material gas and the reactive gas.
14 . The method of claim 13 , wherein
the dopant-containing raw-material gas comprises germanium.
15 . The method of claim 14 , wherein
the dopant-containing raw-material gas is germanium halide gas.
16 . The method of claim 13 , wherein
the reactive gas is an etching gas.
17 . The method of claim 13 , wherein
the reactive gas comprises at least one selected from among hydrogen halide and groups comprising halogen and hydrogen.
18 . The method of claim 13 , wherein
The reactive gas comprises hydrogen halide.
19 . The method of claim 13 , wherein
the substrate comprises a corundum structure.
20 . The method of claim 13 , wherein
the crystalline film has a corundum structure.
21 . The method of claim 13 , wherein the substrate is heated with a temperature that is in a range of 400° C. to 700° C.
22 . The method of claim 13 , wherein
the metal source comprises gallium, and the metal-containing raw-material gas comprises gallium.
23 . The method of claim 13 , wherein
the gasifying the metal source is done by halogenating the metal source.
24 . The method of claim 13 , wherein
the oxygen-containing raw-material gas comprises at least one selected from among oxygen (O 2 ), water (H 2 O) and nitrous oxide (N 2 O).