DEVELOPMENT OF A LOW COST 6 AND 8 INCH SILICON-ON-SAPPHIRE (SOS) SUBSTRATE USING THE EFG TECHNIQUE

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 substates 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.