SBIR-STTR Award

This Phase I effort represents a radically new approach for the synthesis of high purity SiC source material that can solve many of the problems inherent to the boule growth of semi-insulating (SI) silicon carbide (SiC) using the conventional compensation method. The program is aimed at conducting process development and testing to show proof of concept of a novel synthesis technique that will produce very high purity SiC source material. We will also demonstrate that the high purity SiC source material can be produced with high yields and hence low costs. Characterization will be performed on the source material, to demonstrate that it is pure, free of metallic impurities. The high purity SiC source material produced by this technique is conducive to the growth of semi-insulating SiC boules ( >10^8 ohm-cm) with low density of crystallographic defects and with material characteristics (resistivity, defect density) that are uniform across the boule volume. Hence the resulting SI SiC wafers are expected to significantly increase device yield. In Phase II, we will demonstrate the growth of SI SiC boules >50mm in diameter of superior quality, having low density of crystallographic defects and variation in material characteristics <10% across the volume of the boule.Anticipated Benefits/Commercial Applications: With the proposed approach, three specific advantages are anticipated: (a) the high yield of the synthesis process is expected to result in low cost of the pure source material, (b) the high purity source material will produce boules whose characteristics are uniform over its volume ( <10% variation in resistivity and defect density), (c) high wafer yield and reduced cost of SI SiC wafers, which stimulates the widespread commercialization of the material for microwave and RF system applications.

The development of a process to produce semi-insulating (SI) silicon carbide (SiC) boules with improved yields will significantly reduce the cost of wafers and thus accelerate the rapid commercialization of SI SiC for microwave and RF system applications. The objective of this Phase II project is to improve and perfect the process development of a radically new approach for the synthesis of high purity SiC source material that can solve many of the problems inherent to the boule growth of SI SiC using the conventional compensation method. In Phase I, the feasibility of a novel SiC source synthesis method and its applicability for the growth of high resistivity SiC (background doping concentration of <10^4 per cc) boules was demonstrated. In Phase II, the source material synthesis process will be optimized for cost effectiveness, yield, and purity - especially a reduction in metallic impurities. In Phase II, the synthesized high purity source material will be used to demonstrate the growth of SI SiC boules, 50mm in diameter. Anticipated Benefits/Commercial Applications: With the proposed approach, three specific advantages are anticipated: (a) the high yield of the synthesis process is expected to result in low cost of the pure source material, (b) the high purity source material will produce boules whose characteristics are more uniform over their volume, (c) higher wafer yield and reduced cost of SI SiC wafers, which stimulates the widespread commercialization of the material for microwave and RF system applications.

Keywords:
Silicon carbide, high resistivity SiC, SiC, semi-insulating silicon carbide, crystal growth, high power microwave