Ballistic Mobility and Injection Velocity in Nanoscale InGaAs FinFETs

This work presents an experimental study of ballistic transport parameters of nanometer-scale InGaAs FinFETs with fin widths down to 9 nm. In these types of transistors, gate oxide trapping represents a significant confounding factor that leads to severe underestimation of mobility and injection velocity. Using a combination of I-V and S-parameter measurements up to 50 GHz, we extract charge control relationship, mobility and injection velocity in a manner that is immune to oxide trapping. While long-channel mobility is found to degrade in narrower fins, short-channel mobility remains unaffected. This is due to an enhancement in ballistic mobility as fin width narrows. Furthermore, the injection velocity shows no discernable fin width dependence. These results can be explained by channel quantization, as verified by k·p simulations. Importantly, they suggest promising transport characteristics in nanoscale InGaAs FinFET technology, and that long-channel mobility constitutes a poor predictor of short-channel performance of InGaAs FinFETs.