Dual material gate field effect transistor (DMG-FET)

Improving performance and suppressing short channel effects are two of the most important issues in present field effect transistors development. Hence, high performance and long channel like behaviors are essential requirements for short channel FETs. This dissertation focuses on new ways to achieve these significant goals. A new field effect transistor--dual material gate FET (DMG-FET)--is presented for the first time. The unique feature of the DMG-FET is its gate which consists of two laterally contacting gate materials with different work functions. This novel gate structure takes advantage of material work function difference in such a way that charge carriers are accelerated more rapidly in the channel and the channel potential near the source is screened from the drain bias after saturation. Using HFET as a vehicle, it is shown that the drive current and transconductance in DMG-FET are therefore substantially enhanced as compared to conventional FET. Moreover, it is observed that the short channel effects such as channel length modulation, DIBL and hot-carrier effect are significantly suppressed. Numerical simulations are employed to investigate the new device structure and related phenomenon. A simple and practical DMG-HFET fabrication process has been developed. The proposed DMG-HFET is thus realized for the first time. Experimental results exhibit improved characteristics as the simulation results predicted.