A 48.1 PS HEMT DCFL NAND CIRCUIT WITH A DUAL-GATE STRUCTURE

We fabricated HEMT DCFL 2-input NAND circuits and examined their feasi bility using a dual gate structure. Our HEMT had MOVPE-grown InGaP/InG aAs/GaAs pseudomorphic HEMT structures. We first investigated characte ristics of the dual gate HEMT in the short gate length region and show ed that HEMTs can reveal their inherent properties even in the DCFL NA ND circuits. We fabricated a 2-input NAND ring oscillator with a gate length of 0.5 mu m. It successfully operated and showed a propagation delay of 48.1 ps and a power consumption of 0.235 mW per stage at a su pply voltage of 0.8 V. A master-slave type divide-by-two frequency div ider which consists of eight 2-input NAND gates also showed 3.14 GHz o peration with a power consumption of 2 mW.