MONOCRYSTALLINE beta -SIC SEMICONDUCTOR THIN FILMS: EPITAXIAL GROWTH, DOPING, AND FET DEVICE DEVELOPMENT.
High-purity, single-crystal beta -SiC thin films have been epitaxially grown by means of chemical vapor deposition. The defect nature of these films has been characterized, and antiphase boundaries, one of the major defects observed, were eliminated through utilization of off-axis Si substrates. Doping of these films was possible through in-situ incorporation during growth or through ion implantation. The use of elevated temperatures during ion implantation resulted in damage-free material suitable for device fabrication. MESFETs constructed from these films showed good transistor action up to temperature of 523 K. Depletion-mode MOSFETs fabricated on beta -SiC (111) were operated for the first time at temperatures as high as 923 K. Stable saturation and channel cutoff were observed from room temperature to 923 K at drain voltages exceeding 25 V. Transconductances increased with temperature to 573 K and decreased with temperature above 673 K. The maximum transconductance observed was 11. 9 mS/mm on a 2. 4- mu m-channel device at 673 K.
