Short-channel effects in subquarter-micrometer-gate HEMTs: simulation and experiment

The authors studied the electrical properties of subquarter-micrometer-gate HEMTs (high electron mobility transistors) by Monte Carlo simulation and experiment. Simulation shows that subquarter-micrometer-gate HEMTs have extremely high performance, and the near-ballistic movement under the gate was confirmed. It is also shown that the aspect ratio of the channel could be used as a guide to determine the extent of short-channel effects. The transverse-domain formation inherent in short-channel HEMTs may also contribute to the smaller short-channel effect by limiting undesirable substrate current. Experimentally, only a negligible short-channel effect was observed when the gate length was reduced from 1.25 to 0.14 mu m. Thus it is not necessary to design and fabricate a special structure for HEMTs, as such a structure might have limited applications. >