| 摘要 |
A high speed submicron metal-oxide-semiconductor transistor which exhibits a high immunity to hot electron degradation. An inverse T-gate comprising a polysilicon upper member and a tungsten lower member is formed on a p type substrate. A gate insulating layer is formed between the composite gate and the p type substrate. A pair of n- source/drain regions are formed apart in the p type substrate in alignment with the sides of the polysilicon upper member for forming a lightly doped drain region. An oxide sidewall spacer is formed adjacent to each side of the polysilicon upper member on the tungsten lower gate member for forming a mask for a n+ source/drain implant. The n+ source/drain implant is made in the n- source/drain regions in alignment with the oxide sidewall spacers for providing a source and a drain for the transistor. The tungsten lower gate member improves the transistors performance and makes the transistor viable for VLSI manufacturing techniques. The performance of the device can be further improved by placing silicide on the source gate, and drain regions. The reliability of the device can be further improved by grading the doping of the drain an additional time.
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