Extraction of Channel Electron Effective Mobility in InGaAs/Al2O3 n-FinFETs

A compact set of equations based on the multiple subbands quasi-ballistic transport theory is developed, and is used to investigate the channel electron effective mobility in recently reported In0.53Ga0.47As/Al2O3 tri-gate n-FinFET. The extracted electron effective mobility mu(n) is around 370 cm(2)/V.s at low V-g-V-th bias at room temperature and decreases with increasing V-g, and increases with increasing temperature (240-332K). It is very different from the case of Si n-MOSFETs, where the electron mobility decreases with increasing temperature. The low channel effective mobility and the ab-normal temperature dependence of mu(n) are ascribed to the high acceptor interface trap and border trap energy densities in the conduction band energy of InGaAs. The ballistic channel resistance R-Ball at low V-ds is calculated and compared with the measured channel resistance R-CH. The low transmission coefficient T = R-Ball/R-CH approximate to 0.06 to 0.05 indicates that there is a large room to improve the InGaAs/Al2O3 n-FinFET performance.