RESONANT-TUNNELING DIODE AND HEMT LOGIC-CIRCUITS WITH MULTIPLE THRESHOLDS AND MULTILEVEL OUTPUT

By using resonant-tunneling diodes (RTD's) and high electron mobility transistors (HEMT's), we implement a new class of logic circuits that operate with multiple thresholds and multilevel output, The basic idea of the circuits is to synthesize transfer characteristics by key logi c elements, namely, up and down literals, We first describe two fundam ental logic circuits based on this idea: a ternary inverter and a lite ral gate. Then we present experimental results on these circuits fabri cated by integrating InP-based RTD's and HEMT's, It is found that thes e circuits operate successfully with threshold voltages and output lev els that have been predicted from individual device characteristics. C onsequently, the validity of the basic idea behind the circuits presen ted here is proven, The device counts and the number of logic stages r equired for the present circuits are less than half those for conventi onal ones, A possible application is finally discussed.