SHORT-CHANNEL-EFFECT-SUPPRESSED SUB-0.1-MU-M GROOVED-GATE MOSFETS WITH W-GATE

Grooved-gate Si MOSFET's with tungsten gates are fabricated using conventional manufacturing technologies, and their short-channel-effect-free characteristics are verified down to a source and drain separation of around 0.1 mu m. Phase shift lithography followed by a side-wall oxide film formation technique achieves a spacing of less than 0.2 mu m between adjacent elevated polysilicons, subsequently resulting in a sub-0.1-mu m source and drain separation in the substrate. Short-channel effects, such as threshold voltage roll-off and punchthrough, are found to be completely suppressed. From device simulations, the potential barrier formed at each grooved-gate corner is considered to he responsible for the suppression of the short-channel effects.