Electron dynamics and device physics of short-channel HEMTs: Transverse-domain formation, velocity overshoot, and short-channel effects

The authors simulated the electron dynamics and physics in sub-quarter-micron-gate HEMTs (high electron mobility transistors) and fabricated devices for testing their theories on the short-channel effect. They confirmed near-ballistic electron transport under the gate and predicted transverse-domain formation. They introduce a parameter called the channel aspect ratio, which could serve as a design rule for determining the extent of the short-channel effect. Measurements show that the threshold voltage shift is almost negligible for gates as short as 0.14 μm. Thus, within the range studied, HEMTs do require a special design that would limit their applications.