SBIR-STTR Award

Saphikon, Inc. has successfully demonstrated 12 x 24 inch sapphire sheet growth using the Edge Defined Film Fed Growth (EFG) technique. Therefore the focus of this program is to identify and demonstrate solutions to the technical problems imposed by the strict specifications of the "electronic grade" sapphire demanded by SOS applications. The requirements for the sapphire substrate are well understood and many thousands of sapphire substrates have been manufactured by various crystal growth techniques. It is the necessity of meeting these demanding specifications and keeping the cost low that is the problem. There is no doubt that EFG can produce low cost substrates if the yield is high. The presence of dislocations, lineage, polycrystallinity and inclusions have all served to keep this yield low. The identification of the technical solutions to these problems will serve to increase the quality of EFG sapphire to the point of producing truly cost effective 6 and 8 inch sapphire SOS substrates.

Phase I of this program focused on identifying and solving producibility issues with the Edge Defined Film Fed Growth (EFG) technique for producing large diameter single crystal sapphire. Phase I identified, experimentally, solutions to the problem of the occurrence of catastrophic defects in large diameter (150 and 200mm) sapphire substrates for Silicon-on-Sapphire. This resulted in either reducing or eliminating these defects all together. The remaining work to be accomplished in Phase II is to implement these solutions into full scale production of 150 and, especially, the 200 mm sapphire substrates. Phase II will also include the development of fabrication and polishing means for up to 200mm sapphire wafers. Furthermore, Phase II will establish the production techniques and capabilities for producing very thin film silicon-on-sapphire (TFSOS). The requirement is for 300 to 1000 +-2.5% silicon films, which will require very uniform CVD deposition of thicker, 2700 films of very uniform thickness (+-< 15A).