Steady-state and transient electron transport within bulk ternary nitride semiconductors including GaInN, AlGaN and AlInN using a three-valley Monte Carlo method

Abstract

An ensemble Monte Carlo simulation is used to compare bulk electron transport in wurtzite phase GaInN, AlGaN and AlInN materials. Electronic states within the conduction band valleys at the Γ, U and K are represented by non-parabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. For all materials it is found that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material parameters. Transient velocity overshoot has also been simulated with the sudden application of fields up to ~5×10 7 Vm -1 , appropriate to the gate-drain fields expected within an operational field effect transistor. The electron drift velocity relaxes to the saturation value of ~1.5×10 5 ms -1 with in 4 ps for all crystal structures. The steady-state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.