High speed and short channel transport characteristics of scaled sub-100 nm gate high election mobility transistors

Ultra-short channel AlGaAs/GaAs High electron Mobility Transistors have been fabricated with gate lengths ranging from 35 nm to 115 nm, in order to examine the characteristics of sub-100 nm HEMT scaling. Measurements of the transconductance and extraction of the effective electron velocity shaw a initial decrease in these quantities near 50 nm of gate length due to the dominance of short-channel effect. The rise in transconductance below this gate length is attributed to the onset of velocity overshoot in the channel region. We have investigated this behavior by comparison between the effective average electron velocities obtained analytically from the measured transconductance and those calculated numerically from the transient transport model. The results yield qualitative agreement with both the measurements and the interpretation given above.