Methods of growing a silicon carbide epitaxial layer on a substrate to increase and control carrier lifetime
A method of growing an epitaxial layer on a substrate is generally provided. According to the method, the substrate is heated in a chemical vapor deposition chamber to a growth temperature in the presence of a carbon source gas, then the epitaxial layer is grown on the substrate at the growth temperature, and finally the substrate is cooled in a chemical vapor deposition chamber to at least about 80% of the growth temperature in the presence of a carbon source gas. Substrates formed from this method can have a carrier lifetime between about 0.25 μs and about 9.9 μs.
1. A substrate, comprising:
a substrate body defining a surface;
a first carbon deposit directly on the surface of the substrate body, wherein the first carbon deposit is formed in a temperature increase atmosphere that consists essentially of a first carbon source gas and a carrier gas, at least a portion of the first carbon deposit being diffused into the substrate body to fill one or more defects therein;
a silicon carbide epitaxial layer directly on the first carbon deposit; and
a second carbon deposit directly on the silicon carbide epitaxial layer, wherein the second carbon deposit is formed in a temperature decrease atmosphere that consists essentially of a second carbon source gas and a carrier gas, at least a portion of the second carbon deposit being diffused into the silicon carbide epitaxial layer to fill one or more defects therein.
2. The substrate of claim 1 , wherein the silicon carbide epitaxial layer has a carrier lifetime between about 0.25 μs and about 9.9 μs.
3. The substrate of claim 1 , wherein the silicon carbide epitaxial layer has a carrier lifetime between about 1 μs to about 9.5 μs.
4. The substrate of claim 1 , wherein the silicon carbide epitaxial layer has a carrier lifetime between about 5 μs to about 9 μs.
5. The substrate of claim 1 , wherein the substrate body comprises silicon carbide.
6. The substrate of claim 5 , wherein the silicon carbide has a crystal structure that defines a hexagonal unit cell.