Abstract of Research The objective of this research is to develop novel transistors which can provide high output currents with very low input voltage swings. The "subthreshold swing" of the transistors will be less than 20mV/decade, substantially below the 60 mV/decade limit for current transistors. The proposed transistors will overcome a significant problem for the continued progress of Moore's Law, the rapidly increasing power dissipation in CMOS circuits when they are scaled to small dimensions. The approach is to use source-channel heterojunctions based on III-V materials with staggered band offsets. The transistors operate by tunneling rather than by thermionic injection of carriers into the channel. Tunneling transistors employing Si have been previously proposed. With InGaAs/AlGaSb materials, staggered heterojunctions can be engineered with higher tunneling probability than with Si. At the same time, the excellent transport characteristics of III-V's can maintain high current and high speed.
The intellectual merit of this proposal is based on the fact it explores a rich new area of semiconductor science, with new physical principles for FET operation based on control over the current by heterojunction engineering. The payoff of the project can be of immense importance for CMOS technology.
The broader impact of this program derives from its importance for the training of next generation semiconductor device physicists; from research training of undergraduates through lectures as part of a Freshman seminar series and mentoring of an undergraduate student engaged in the research; and through interaction with secondary students at UCSD's Preuss School.
