Crystalline multilayer structure and semiconductor device
Provided is a crystalline multilayer structure which has good electrical properties and is useful for semiconductor devices. A crystalline multilayer structure includes a base substrate and a crystalline oxide semiconductor thin film disposed directly on the base substrate or with another layer therebetween and including a corundum-structured oxide semiconductor as a major component. The oxide semiconductor contains indium and/or gallium as a major component. The crystalline oxide semiconductor thin film contains germanium, silicon, titanium, zirconium, vanadium, or niobium.
1. A crystalline multilayer structure comprising:
a base substrate; and
a crystalline oxide semiconductor thin film disposed directly on the base substrate or with another layer therebetween and comprising a corundum-structured oxide semiconductor as a major component,
wherein the oxide semiconductor contains one or both of indium or gallium as a major component, and
wherein the crystalline oxide semiconductor thin film contains germanium and is substantially free of carbon.
2. The crystalline multilayer structure of claim 1 , wherein the crystalline oxide semiconductor thin film contains germanium.
3. The crystalline multilayer structure of claim 1 , wherein a concentration of germanium in the crystalline oxide semiconductor thin film is 1×10 16 /cm 3 to 1×10 22 /cm 3 .
4. The crystalline multilayer structure of claim 1 , wherein a concentration of germanium in the crystalline oxide semiconductor thin film is 1×10 17 /cm 3 or less.
5. The crystalline multilayer structure of claim 1 , wherein a concentration of germanium in the crystalline oxide semiconductor thin film is 1×10 20 /cm 3 or more.
6. The crystalline multilayer structure of claim 1 , wherein the oxide semiconductor is α-phase In X Al Y Ga Z O 3 in which 0≦X≦2, 0≦Y≦2, 0≦Z≦2, X+Y+Z=1.5 to 2.5, and 0<X or 0<Z.
7. A semiconductor device comprising the crystalline multilayer structure of claim 1 .
8. A semiconductor device comprising the crystalline multilayer structure of claim 1 and an electrode.
9. A semiconductor device comprising:
a semiconductor layer comprising a crystalline oxide semiconductor thin film containing a corundum-structured oxide semiconductor as a major component; and
an electrode,
wherein the oxide semiconductor contains one or both of indium or gallium as a major component, and
wherein the crystalline oxide semiconductor thin film contains germanium and is substantially free of carbon.
10. The semiconductor device of claim 7 , wherein the semiconductor device is a vertical device.
11. The semiconductor device of claim 7 , wherein the semiconductor device is a power device.
12. The semiconductor device of claim 7 , wherein the semiconductor device is a Schottky barrier diode (SBD), a metal semiconductor field-effect transistor (MESFET), a high-electron-mobility transistor (HEMT), a metal oxide semiconductor field-effect transistor (MOSFET), a static induction transistor (SIT), a junction field-effect transistor (JFET), an insulated gate bipolar transistor (IGBT), or a light-emitting diode (LED).
13. The semiconductor device of claim 7 , wherein the semiconductor device is a Schottky barrier diode (SBD), a metal oxide semiconductor field-effect transistor (MOSFET), a metal semiconductor field-effect transistor (MESFET), a high-electron-mobility transistor (HEMT), or a static induction transistor (SIT).