Overshoot Saturation in Ultra-Short Channel Fets due to Minimum Acceleration Lengths.

摘要

The existence of velocity overshoot in FETs can be used to enhance their characteristics if the devices can be fabricated small enough to utilize this effect. The velocity over-shoot can also be used to increase the frequency response of the MESFETs if the drain can collect the electrons within a few inelastic mean free paths of the gate. For this case, the electrons will spend a larger portion of their transit time in the overshoot region, and the transit time will decrease, thus increasing the transconductance. From the wide range of reported transconductances in the literature for small-gate MESFETs, a comparison is difficult. Although variations in doping and active layer thicknesses can be determined, differences due to fabrication techniques are difficult to accurately estimate. By fabricating MESFETs with varying gate lengths and doping, this uncertainty can be eliminated. Reprints. (rrh)