EPITAXIAL GROWTH OF SILICON CARBIDE ON SAPPHIRE
remove impurities from an exposed surface in the ultrahigh vacuum environment. A high qualify single crystalline or polycrystalline silicon carbide film can be grown directly on the sapphire substrate by chemical vapor deposition employing a silicon-containing reactant and a carbon-containing reactant. Formation of single crystalline silicon carbide has been verified by x-ray diffraction, secondary ion mass spectroscopy, and transmission electron microscopy.
1 . A method of forming a semiconductor-carbon alloy layer on a sapphire substrate, said method comprising:
placing a sapphire substrate in a vacuum environment; and
providing a semiconductor-containing precursor and a carbon-containing precursor into said vacuum environment, wherein a single crystalline semiconductor-carbon alloy layer is epitaxially formed directly on a crystallographic surface of said sapphire substrate.
2 . The method of claim 1 , wherein an entirety of said sapphire substrate is single crystalline.
3 . The method of claim 1 , wherein said semiconductor-containing precursor includes silicon and said carbon-containing precursor includes carbon and hydrogen.
4 . The method of claim 3 , wherein said semiconductor-containing precursor is selected from SiH 4 , Si 2 H 6 , SiH 3 Cl, SiH 2 Cl 2 , SiHCl 3 , and SiCl 4 .
5 . The method of claim 3 , wherein said carbon-containing precursor is selected from C 2 H 2 , C 2 H 4 , C 2n-2 , and C n H 2n , wherein n is an integer greater than 2.
6 . The method of claim 3 , wherein said vacuum environment is provided by an ultrahigh vacuum chamber having a base pressure less than 1.0×10 −6 Ton.
7 . The method of claim 1 , wherein said single crystalline semiconductor-carbon alloy layer is a single crystalline silicon-carbon alloy layer.
8 . The method of claim 7 , wherein said single crystalline semiconductor-carbon alloy layer has an atomic carbon concentration from 40% to 60%.
9 . The method of claim 8 , wherein said single crystalline semiconductor-carbon alloy layer is a single crystalline silicon carbide layer having a hexagonal or cubic crystal structure.
10 . The method of claim 1 , wherein the said semiconductor-carbon alloy layer includes at least one polycrystalline semiconductor-carbon alloy portion.
11 . The method of claim 10 , wherein said semiconductor-carbon alloy layer has an atomic carbon concentration from 40% to 60%.
12 . The method of claim 11 , wherein said semiconductor-carbon alloy layer includes a mixture of at least one polycrystalline silicon carbide portion having a hexagonal or cubic crystal structure.
13 . The method of claim 1 , wherein said single crystalline semiconductor-carbon alloy layer is deposited with a (0001) surface orientation and a hexagonal crystal structure directly on a (0001) plane of said sapphire substrate.
14 . The method of claim 1 , wherein said single crystalline semiconductor-carbon alloy layer is deposited with a (111) surface orientation and a cubic crystal structure directly on a (1102) plane of said sapphire substrate.
15 . The method of claim 1 , wherein said single crystalline semiconductor-carbon alloy layer is deposited at a temperature from 800° C. to 2,000° C.
16 . A structure comprising a single crystalline semiconductor-carbon alloy layer located directly on a crystallographic surface of a sapphire substrate.
17 . The structure of claim 16 , wherein an entirety of said single crystalline semiconductor-carbon alloy layer is epitaxially aligned to a crystallographic lattice of said sapphire substrate.
18 . The structure of claim 16 , wherein an entirety of said sapphire substrate is single crystalline.
19 . The structure of claim 16 , wherein said single crystalline semiconductor-carbon alloy layer is a single crystalline silicon-carbon alloy layer.
20 . The structure of claim 19 , wherein said single crystalline semiconductor-carbon alloy layer has an atomic carbon concentration from 40% to 60%.
21 . The structure of claim 20 , wherein said single crystalline semiconductor-carbon alloy layer is a single crystalline silicon carbide layer having a hexagonal or cubic crystal structure.
22 . The structure of claim 16 , wherein said single crystalline semiconductor-carbon alloy layer has a hexagonal crystal structure, wherein a (0001) surface of said single crystalline semiconductor-carbon alloy layer contacts a (0001) plane of said sapphire substrate at an interface.
23 . The structure of claim 16 , wherein said single crystalline semiconductor-carbon alloy layer has a cubic crystal structure, wherein a (111) surface of said single crystalline semiconductor-carbon alloy layer contacts a (1102) plane of said sapphire substrate at an interface.
24 . A structure comprising at least one polycrystalline semiconductor-carbon alloy layer located directly on a crystallographic surface of a sapphire substrate.
25 . The structure of claim 24 , wherein grains of said at least one polycrystalline semiconductor-carbon alloy portion has a hexagonal crystal structure, wherein a (0001) surface of said at least one polycrystalline semiconductor-carbon alloy portion contacts a (0001) plane of said sapphire substrate at an interface.