Oxide interfacial charge engineering towards normally-off AlN/GaN MOSHEMT

In this paper a detail insight into the role of oxide/barrier interfacial charges (Nox) for shifting the threshold voltage (VT) of AlN/GaN metal oxide semiconductor high electron mobility transistors (MOSHEMTs) is gained. A model is developed for VT considering all possible charges arise at different interfaces. To validate the model the proposed device is simulated by considering different insulators and Nox into account. It is very fascinating to observe that VT is highly sensitive towards change in Nox at higher oxide dimensions, whereas at lower dimensions Nox has very negligible effect. Normally-off operation can be achieved by increasing or decreasing Nox in MOSHEMT with Al2O3 or HfO2 as gate dielectric respectively.