Compound semiconductor, method for manufacturing same, and nitride semiconductor
A compound semiconductor has a high electron concentration of 5×10 19 cm −3 or higher, exhibits an electron mobility of 46 cm 2 /V·s or higher, and exhibits a low electric resistance, and thus is usable to produce a high performance semiconductor device. The present invention provides a group 13 nitride semiconductor of n-type conductivity that may be formed as a film on a substrate having a large area size at a temperature of room temperature to 700° C.
1. A two-, three-, or four-component compound semiconductor containing nitrogen and one element selected from the group consisting of B, Al, Ga and In, which are group 13 elements,
wherein:
the compound semiconductor has a thin film shape,
the compound semiconductor contains Si or Ge as an electron donor,
the compound semiconductor contains oxygen as an impurity at 1×10 17 cm −3 or higher,
in a case where the compound semiconductor contains Si as the electron donor, the compound semiconductor has an electron concentration of 8.09×10 19 cm −3 or higher and has n-type conductivity,
in a case where the compound semiconductor contains Ge as the electron donor, the compound semiconductor has an electron concentration of 3.04×10 20 cm −3 or higher and has n-type conductivity, and
the compound semiconductor exhibits an electron mobility, measured at room temperature, of 46 cm 2 /V·s or higher.
2. The compound semiconductor according to claim 1 , wherein the compound semiconductor contains GaN.
3. The compound semiconductor according to claim 2 , wherein the compound semiconductor has an absorption coefficient of 2000 cm −1 or lower to light having a wavelength region of 405 nm.
4. The compound semiconductor according to claim 2 , wherein the compound semiconductor has an absorption coefficient of 1000 cm −1 or lower to light having a wavelength region of 450 nm.
5. The compound semiconductor according to claim 1 , wherein the compound semiconductor has an RMS value of 5.0 nm or less obtained by a surface roughness measurement performed by an AFM.
6. The compound semiconductor according to claim 1 , wherein the compound semiconductor has a contact resistance, measured at room temperature, of 1×10 −4 Ω·cm 2 or lower against an n-type ohmic electrode metal.
7. The compound semiconductor according to claim 1 , wherein the compound semiconductor contains Ga as the group 13 element and further contains Al and/or In as the group 13 element.
8. A contact structure comprising a conductive portion and an electrode connected with each other, the conductive portion being formed using the compound semiconductor according to claim 1 .
9. A semiconductor device comprising the contact structure according to claim 8 .
10. A transparent electrode formed using the compound semiconductor according to claim 1 .
11. A method for manufacturing a compound semiconductor, the method comprising forming a film using the compound semiconductor according to claim 1 by a pulse sputtering method in a process atmosphere containing oxygen.
12. The method for manufacturing a compound semiconductor according to claim 11 , wherein the film is formed at a substrate temperature of 700° C. or lower.