Subthreshold current in MODFETs of tenth-micrometer gate

The subthreshold current of conventional GaAs/AlGaAs MODFETs and pseudomorphic InGaAs/AlGaAs MODFETs with the gate length down to 0.12 mu m is investigated. The gate swing increases with the drain voltage and decreases with the gate length. It is attributed 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/AlGaAs MODFETs show much better control than the conventional GaAs/AlGaAs MODFETs 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.<
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