Circuit Performance of Complementary Heterostructure Misfet Inverter using High Mobility 2DEG and 2DHG

A complementary circuit employing high mobility two-dimensional electron and hole gases(2DEG and 2DHG) induced at the AlGaAs/GaAs heterointerface has been successfully fabricated on an n⁺ -Ge/undoped AlGaAs/undoped GaAs heterostructure. Transfer characteristics of a two-stage inverter show sufficiently high and low output levels. A 15-stage ring oscillator shows a minimum delay time of 94 ps at 300 K and 64 ps at 77 K. The circuit simulation using a new gate current model shows that, for mul ti-input logic gate, a NAND gate configuration is superior to a NOR gate configuration, and that a high speed operation below 20 ps at 77 K is possible by reducing the gate length to 0.5µm.