SUBTHRESHOLD CURRENT IN MODFETS OF 10TH-MICROMETER GATE

We have investigated the subthreshold current of conventional GaAs/AlGaAs MODFET’s and pseudomorphic InGaAs/AIGaAs MODFET’s with the gate length down to 0.12 μm. The gate swing increases with the drain voltage and decreases with the gate length. It is interpreted as due to charge injection from source to drain, limited by the channel potential barrier, which is a function of both the drain and the gate voltages. The pseudomorphic InGaAs/AIGaAs MODFET's show much better control than tbe conventional GaAs/AlGaAs MODFET’s for the subthreshold current, especially with high drain biases. This shows that the pseudomorphic quantum-well structures can suppress the subthreshold current passing through the GaAs buffer region and reduce the undesirable short-channel effects. © 1990 IEEE