Doped polycrystalline sic wafer with improved flatness and electrical conductivity, and method for producing such a wafer
AssigneeMersen France Gennevilliers SAS
InventorsAlexandre POTIER, Marc FERRATO, Christophe BOMMIER
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Abstract
A polycrystalline SiC plate having a preferential crystalline orientation, the plate having on each of its faces: its texture coefficient C422 is less than 40%, and its texture coefficient C220+C200+C400 is greater than 50%, and preferably greater than 80%. This plate can be manufactured by a CVD process. The raw blank thus obtained can be thinned by grinding and polishing. Its flatness, electrical conductivity and thermal conductivity, which are important properties for use as a substrate in microelectronics, can be improved by heat treatment.
Claims19
1-24. (canceled)
A beta-type polycrystalline SiC plate with a preferential crystalline orientation, the beta-type polycrystalline SiC plate comprising:
- a plate structure having on each face thereof:
- (i) its texture coefficient C422 is less than 40%, and (ii) a texture coefficient C220+C200+C400 greater than 80%.
A method for manufacturing a polycrystalline SiC plate, comprising:
- forming a polycrystalline SiC layer on a graphite surface of a substrate by chemical vapor deposition (CVD), the CVD including a mixture of gases introduced into a heated enclosure to create a gas mixture comprising:
- at least one gaseous silicon and/or carbon precursor, at least one doping gas comprising at least one nitrogen atom, and a carrier gas, wherein the gas mixture decomposes on the graphite surface to form the polycrystalline SiC layer, wherein the temperature in the heated enclosure is between 1450 K and 1650 K and the total partial pressure of said gaseous precursors is less than 300 mbar;
- and
- supporting the substrate on a flat surface while performing at least one heat treatment step of the polycrystalline SiC layer at a temperature between 1950° C. and 2150° C.
Dependencies are inferred from the claim text.