RTD/2-D MESFET logic element for compact, ultra-low-power electronics

We describe compact and highly functional logic elements utilizing a two-dimensional (2-D) MESFET with a resonant tunneling diode load. The 2-D MESFET uses two lateral Schottky gate contacts to modulate the width of the 2-D electron gas layer. The novel contact geometry results in reduced gate capacitance, ultra-low-power performance, and the elimination of the Narrow Channel Effect (NCE) compared to conventional HFETs or MESFETs. The advantage of using an RTD as the load device is the reduction of the static power consumption at the logical high input level. We demonstrate low-power RTD/2-D MESFET inverter operation as well as compact NAND and NOR gates using a single RTD/2-D MESFET pair. We also present optimized inverter elements and estimate from SPICE simulations the power-delay products of RTD/2-D MESFET ring oscillators. Compared to recently reported values for CMOS on SOI, the RTD/2-D MESFET technology is expected to exhibit one order of magnitude less active power dissipation and a factor of 3 lower power-delay product.