Electron mobility in InxGa1-xN channel HEMTs

Abstract: In this letter, we report on the theoretical investigations of electron mobility in practically viable designs of InxGa1-xN channel high electron mobility transistors (HEMT). Carriers in such devices are expected to exhibit a higher velocity and hence higher cut-off frequencies (fT) for highly scaled architectures. We estimate that the mobility of two dimensional electron gas (2DEG) is limited by alloy scattering rather than phonon scattering unlike in conventional GaN-channel HEMTs. For indium composition of 0.30, the mobility and sheet resistance are found to be 500 cm2/Vs and 700 ohm per sq. respectively, which can severely affect the parasitic voltage drop in access regions. The results presented here are believed to significantly guide the practical exploration of InxGa1-xN channel HEMTs towards next-generation electronics by enabling careful design of device layouts in highly scaled transistors to minimize parasitic access region voltage drop which results due to significant degradation of 2DEG mobility.