ANALYTICAL STUDY OF CONDUCTION BAND DISCONTINUITY SUPPORTED 2DEG DENSITY IN AlN/Ga2O3 HEMT

Apart from other factors, band alignment led conduction band offset (CBO) largely affects the two dimensional electron gas (2DEG) density ns in wide bandgap semiconductor based high electron mobility transistors (HEMTs). In the context of assessing various performance metrics of HEMTs, rational estimation of CBO and maximum achievable 2DEG density is critical. Here, we present an analytical study on the effect of different energy band parameters—energy bandgap and electron affinity of heterostructure constituents, and lattice temperature on CBO and estimated 2DEG density in quantum triangular-well. It is found that at thermal equilibrium, ns increases linearly with ΔEC at a fixed Schottky barrier potential, but decreases linearly with increasing gate-metal work function even at fixed ΔEC, due to increased Schottky barrier heights. Furthermore, it is also observed that poor thermal conductivity led to higher lattice temperature which results in lower energy bandgap, and hence affects ΔEC and ns at higher output currents.