SiC epitaxial wafer, manufacturing apparatus of SiC epitaxial wafer, fabrication method of SiC epitaxial wafer, and semiconductor device
A SiC epitaxial wafer includes: a substrate having an off angle of less than 4 degrees; and a SiC epitaxial growth layer disposed on the substrate having the off angle of less than 4 degrees, wherein an Si compound is used for a supply source of Si, and a C compound is used as a supply source of C, for the SiC epitaxial growth layer, wherein the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm 2 ; and a C/Si ratio of the Si compound and the C (carbon) compound is within a range of 0.7 to 0.95. There is provide a high-quality SiC epitaxial wafer excellent in film thickness uniformity and uniformity of carrier density, having the small number of surface defects, and capable of reducing costs, also in low-off angle SiC substrates on SiC epitaxial growth.
1. A SiC epitaxial wafer comprising:
a substrate having low-off angle of less than 4 degrees; and
a SiC epitaxial growth layer disposed on the substrate, wherein
an Si compound is used for a supply source of Si, and a Carbon (C) compound is used as a supply source of Carbon (C), for the SiC epitaxial growth layer, wherein
the uniformity of carrier density is less than 10%, and the defect density is less than 0.5 count/cm 2 ; and a C/Si ratio between the Si compound and the Carbon (C) compound is within a range of 0.7 to 0.95,
the SiC epitaxial growth layer comprises
a buffer layer disposed on the substrate, and
a drift layer disposed on the buffer layer, and
the C/Si ratio of the Si compound and the Carbon (C) compound in the buffer layer is controlled to be lower than the C/Si ratio of the Si compound and the Carbon (C) compound in the drift layer.
2. The SiC epitaxial wafer according to claim 1 , wherein the off angle is 2 degrees.
3. The SiC epitaxial wafer according to claim 1 , wherein
a growth temperature of the SiC epitaxial growth layer is within a range of 1630° C. to 1690° C.
4. The SiC epitaxial wafer according to claim 1 , wherein
a growth pressure of the SiC epitaxial growth layer is within a range of 3 kPa to 11 kPa.
5. The SiC epitaxial wafer according to claim 1 , wherein
the Si compound comprises one material selected from the group consisting of SiH 4 , SiH 3 F, SiH 2 F 2 , SiHF 3 , and SiF 4 .
6. The SiC epitaxial wafer according to claim 1 , wherein
the C compound comprises one material selected from the group consisting of C 3 H 8 , C 2 H 4 , C 2 H 2 , CF 4 , C 2 F 6 , C 3 F 8 , C 4 F 6 , C 4 F 8 , C 5 F 8 , CHF 3 , CH 2 F 2 , CH 3 F, and C 2 HF 5 .
7. The SiC epitaxial wafer according to claim 1 , wherein
the SiC epitaxial growth layer comprises one material selected from the group consisting of 4H—SiC, 6H—SiC, 2H—SiC, and 3C—SiC.
8. The SiC epitaxial wafer according to claim 1 , wherein
a diameter of the substrate is equal to or greater than 100 mm.
9. The SiC epitaxial wafer according to claim 1 , wherein
the substrate comprises one material selected from the group consisting of 4H—SiC, 6H—SiC, BN, AlN, Al 2 O 3 , Ga 2 O 3 , diamond, carbon, and graphite.
10. A manufacturing apparatus of a SiC epitaxial wafer comprising:
a gas injection port;
a gas exhaust port;
a heating unit; and
a reactor, wherein
a material gas supplied when forming the SiC epitaxial growth layer on the substrate having the off angle of less than 4 degrees contains an Si compound used as a supply source of Si, and Carbon (C) compound used as a supply source of Carbon (C), wherein
the uniformity of carrier density is less than 10%, and the defect density is less than 1 count/cm 2 ; and a C/Si ratio between the Si compound and the Carbon (C) compound is within a range of 0.7 to 0.95.
11. The manufacturing apparatus according to claim 10 , wherein
the SiC epitaxial growth layer comprises a buffer layer disposed on the substrate, and a drift layer disposed on the buffer layer, wherein
the uniformity of carrier density is less than 10%, and the defect density is less than 0.5 count/cm 2 ; and the C/Si ratio of the Si compound and the Carbon (C) compound in the buffer layer is controlled to be lower than the C/Si ratio of the Si compound and the Carbon (C) compound in the drift layer.
12. The manufacturing apparatus according to claim 10 , wherein
the off angle is 2 degrees.
13. The manufacturing apparatus according to claim 10 , wherein
a growth pressure of the SiC epitaxial growth layer is within a range of 3 kPa to 11 kPa.
14. The manufacturing apparatus according to claim 10 , wherein
the Si compound comprises one material selected from the group consisting of SiH 4 , SiH 3 F, SiH 2 F 2 , SiHF 3 , and SiF 4 , wherein
the C compound comprises one material selected from the group consisting of C 3 H 8 , C 2 H 4 , C 2 H 2 , CF 4 , C 2 F 6 , C 3 F 8 , C 4 F 6 , C 4 F 8 , C 5 F 8 , CHF 3 , CH 2 F 2 , CH 3 F, and C 2 HF 5 .
15. The manufacturing apparatus according to claim 10 , wherein
the reactor comprises a vertical-type reactor, wherein
a plurality pieces of the SiC epitaxial wafers can be disposed so as to be parallel to the flow of the gas, in the vertical-type reactor.
16. The manufacturing apparatus according to claim 10 , wherein
the reactor comprises a horizontal-type reactor, wherein
a plurality pieces of the SiC epitaxial wafers can be vertically arranged in an upward direction stand so as to be opposite to the flow of gas, in the horizontal-type reactor.
17. The manufacturing apparatus according to claim 10 , wherein
at least one of H 2 , Ar, HCl, and F 2 is applicable as a carrier gas.
18. The manufacturing apparatus according to claim 10 , wherein
a material of dopant comprises one selected from the group consisting of N2 and Trimethylaluminium.
19. A semiconductor device comprising a SiC epitaxial wafer, wherein the SiC epitaxial wafer comprises:
a substrate having low-off angle of less than 4 degrees; and
a SiC epitaxial growth layer disposed on the substrate, wherein
an Si compound is used for a supply source of Si, and a Carbon (C) compound is used as a supply source of Carbon (C), for the SiC epitaxial growth layer, wherein
the uniformity of carrier density is less than 10%, and the defect density is less than 0.5 count/cm 2 ; and a C/Si ratio between the Si compound and the Carbon (C) compound is within a range of 0.7 to 0.95,
the SiC epitaxial growth layer comprises
a buffer layer disposed on the substrate, and
a drift layer disposed on the buffer layer, wherein
the C/Si ratio of the Si compound and the Carbon (C) compound in the buffer layer is controlled to be lower than the C/Si ratio of the Si compound and the Carbon (C) compound in the drift layer.