Method for Producing Semi-Insulating Resistivity in High Purity Silicon Carbide Crystals
AssigneeCree, Inc.
InventorsJason Ronald Jenny, David Phillip Malta, Hudson McDonald Hobgood, Stephan Mueller, Valeri F. Tsvetkov
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Abstract
A method is disclosed for producing high quality semi-insulating silicon carbide crystals in the absence of relevant amounts of deep level trapping elements. The invention includes the steps of heating a silicon carbide crystal having a first concentration of point defects to a temperature that thermodynamically increases the number of point defects and resulting states in the crystal, and then cooling the heated crystal at a sufficiently rapid rate to maintain an increased concentration of point defects in the cooled crystal.
Claims21
A semi-insulating silicon carbide crystal having a concentration of point defects higher than a thermodynamic equilibrium concentration of point defects at room temperature made by the method of:
- heating a silicon carbide crystal having a first concentration of point defects to a temperature that thermodynamically increases the concentration of point defects in the crystal;
- and
- cooling the heated crystal at a sufficiently rapid rate to maintain an increased concentration of point defects in the cooled crystal.
A semi-insulating silicon carbide crystal made by the method of:
- heating a silicon carbide single crystal to a temperature of at least about 2000° C. to thereby thermodynamically increase the number of point defects and resulting deep level states in the crystal;
- and
- cooling the heated crystal to approach room temperature at a sufficiently rapid rate to maintain a concentration of point defects in the cooled crystal that remains greater than the first concentration.
A wafer and epitaxial layer produced by the method of:
- heating a silicon carbide substrate wafer to a temperature of at least about 2000° C.;
- cooling the heated wafer to 1200° C. or less at a rate of at least about 30° C. per minute;
- and
- depositing an epitaxial layer of a semiconductor material on the substrate wafer.
A wafer and epitaxial layer thereon formed by the method of heating a silicon carbide boule to a temperature of at least about 2000° C.;
- cooling the heated boule to approach room temperature at a rate of at least about 30° C. per minute;
- slicing a silicon carbide wafer from the boule;
- and
- depositing an epitaxial layer of a semiconductor material on the sliced wafer.
A wafer and epitaxial layer thereon formed by the method of
- slicing a silicon carbide wafer from a single crystal silicon carbide boule;
- heating the sliced wafer to a temperature of at least about 2000° C.;
- cooling the heated wafer to approach room temperature at a rate of at least about 30° C. per minute;
- and
- depositing an epitaxial layer of a semiconductor material on the sliced wafer.
A method of producing high quality semi-insulating silicon carbide crystals, the method comprising:
- heating a silicon carbide crystal having a first concentration of point defects to a temperature that thermodynamically increases the concentration of point defects in the crystal;
- and
- cooling the heated crystal at a sufficiently rapid rate to maintain an increased concentration of point defects in the cooled crystal.
Dependencies are inferred from the claim text.