Analysis of effective mobility and hall effect mobility in high-k based In_0.75Ga_0.25As metal-oxide-semiconductor high-electron-mobility transistors

We report an In_0.75Ga_0.25As metal-oxide-semiconductor high-electron-mobility transistor with a peak Hall mobility of 8300 cm ²/Vs at a carrier density of 2 × 10¹² cm ^-2. Comparison of split capacitance-voltage (CV) and Hall Effect measurements for the extracted electron mobility have shown that the split-CV can lead to an overestimation of the channel carrier concentration and a corresponding underestimation of electron mobility. An analysis of the electron density dependence versus gate voltage allows quantifying the inaccuracy of the split-CV technique. Finally, the analysis supported by multi-channel conduction simulations indicates presence of carriers spill over into the top InP barrier layer at high gate voltages.