A novel high-frequency power FET structure fabricated using LPCVD WSi/sub 2/ gate and LCPVD W source contact technology

A novel high-frequency power FET technology is reported that is based on the application of blanket-deposited LPCVD (low-pressure chemical vapor deposition) WSi/sub 2/ to reduce the gate sheet resistance and selectively deposited LPCVD W to improve the source and gate contact resistances. Power FETs capable of blocking 45 V and 90 V in the off-state have been fabricated using this technology, with unprecedented high-frequency performance and excellent wafer yield. These devices have the lowest specific-on-resistance-specific-input-capacitance product ever reported, with transient switching times of less than 7 ns and the capability of switching more than 500 A/cm/sup 2/. For the first time, power FETs with integral Schottky diodes are reported which have resulted in significant enhancement in the reverse recovery characteristics of the parasitic body p-n junction diode of a conventional power MOSFET.<
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