Charge control studies for an AlInN/InN heterojunction field effect transistor without and with oxide layer

This paper describes a novel AlInN/InN heterojunction field effect transistor (HFET) without and with an oxide layer for high performance. A charge control model based on the self-consistent solution of one dimensional Schrodinger-Poisson equations is developed. The model takes into account the highly dominant spontaneous and piezoelectric polarization effects to predict the two dimensional electron gas (2DEG) sheet density more accurately at the heterointerface. The band profile is calculated for the first two sub band energy for In mole fraction of m = 0.1. A large conduction band offset of about 2.77eV is found, which ensure the better confinement and higher sheet charge density. An extremely high two dimensional electron sheet density of 1.21×10¹⁴ cm^-2 is calculated at the hetero interface for In content of 0.1, while those using an oxide layer beneath the gate the 2DEG changes to be 1.99×10¹⁴ cm^-2. It is increased by almost one order of magnitude as compared to ~1×10¹³ cm^-2 obtained in a conventional GaN-based heterostructure. This analysis is expected to provide powerful means to evaluate the performance of AlInN/InN heterostructure field effect transistors and to optimize their design.