Effect of post deposition annealing for high mobility 4H-SiC MOSFET utilizing lanthanum silicate and atomic layer deposited SiO2

We have demonstrated high mobility Si-face 4H-SiC MOSFET results using a novel lanthanum silicate (LaSiO_x) interface engineering and Atomic Layer Deposited (ALD) SiO₂. In this work, the impact of post deposition annealing (PDA) conditions on the mobility of MOSFET with LaSiO_x is investigated. The sample received 900 °C PDA in nitrous oxide (N₂O) ambient shows the highest mobility and higher PDA temperature reduces the peak mobility. Mobility results measured at elevated temperatures show that the electron mobility of the La-containing devices is limited by the phonon scattering as opposed to the coulombic scattering, indicating improved interface properties.