Continued development and characterization of doped layers, contacts and associated electronic devices in silicon carbide

Electronic devices for microwave applications, the science and technology of ohmic and Schottky contacts and equipment fabrication for ultra-high purity thin films were the subjects of concern for the application of growth of the 6H SiC polytype in this reporting period. MESFETs having gate lengths of 2, 4, 13 and 24 microns with maximum transconductances in the range of 1.5 to 22 ms/mm, respectively and with very low subthreshold leakage currents were fabricated. The 2 micron OdB at approx. 380 MHz. IMPATT based on Schottky diodes showed permanent breakdown; those based on p-n junctions appear promising. Ohmic and Schottky contacts are important for devices; thus, a program to examine the interface chemistry and associated electrical properties of high purity contacts deposited under controlled conditions, have been initiated. A molecular beam epitaxy system for the deposition of high purity SiC films is also nearing completion.