Noncoplanar High Power FET.
Annual rept. no. 3, Jan-Dec 77,
VARIAN ASSOCIATES INC PALO ALTO CA
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By using a p Ge-doped substrate and an MBE active layer, common-gate noncoplanar power FET devices were fabricated. Evaluation revealed that the most serious problem with this run was the poor leakage characteristics of the p-n junction gates. A noncoplanar device run was completed from start to finish for the first time. Cd autodoping in the vee and field growths necessitated going to p Ge-doped substrates, and failure to grow continuous VPE active layers over the vees necessitated going to MBE active layer growth where a sputter clean could be done before growth. It was found that a W-Ti barrier was needed between the ohmic contacts and the overlay metal to preserve the low contact resistance and overlay conductivity. These first devices suffered from metallization breaks over the mesa edge, a conducting field growth and high gate leakage current. Consequently, no device characteristics were obtained from this run. Author
- Electrical and Electronic Equipment
- Solid State Physics