A Method for Micropipe Free Silicon Carbide Homoepitaxy

Silicon carbide (SiC) is the ideal semiconductor for fabrication of solid state devices for power conditioning for the all-electric airplane, turbine engine actuators, and space-based power systems. These applications require switches and amplifiers capable of large currents with relatively low voltage drops. The potential for improved performance is indicated by SiC's material characteristics. For example, the breakdown characteristics of a semiconductor are very important in determining the safe operating area (SOA) of a power device fabricated from that material. The measured electric breakdown field for SiC is in the range of 2-4x10 6 V/cm depending on the doping range, and is about 8-10 times higher than that of Si. This indicates that devices fabricated from SiC should be capable of supporting large DC and AC voltages. This permits the devices to amplify and switch large power levels. Due to its large band gap, SiC devices may operate at temperatures up to 700 Degrees C. The limiting factor of SiC for high power devices is currently a high defect density in SiC substrates, particularly a high density of micropipes. The latest results on liquid phase epitaxy (LPE) of silicon carbide presents the opportunity to eliminate micropipes in the epitaxial layer and significantly reduce the density of other types of defects. The micropipe free epitaxial structures grown by the proposed liquid phase technique may be used as substrates for further epitaxial growth by CVD or MBE to obtain the desired device structure, or may be used as a seed for subsequent SiC bulk growth. The primary objective of Phase I of this program is to prove that liquid phase epitaxial growth may provide micropipe free silicon carbide. The development of LPE growth process for micropipe free silicon carbide layers on 2" wafers and fabrication of high-power large area SiC devices on this material will be the primary objective of Phase II. OPTION: None submitted.