Monte Carlo evaluations of degeneracy and interface roughness effects on electron transport in AlGaN-GaN heterostructures

Calculations of the electronic mobility and drift velocity have been carrie d out for bulk GaN and AlGaN-GaN heterojunctions based on a Monte Carlo app roach. The bulk calculations were intended to serve as a validity check of the simulation model. For the heterojunction electron mobility calculations , polarization effects, degeneracy, and interface roughness scattering were all taken into account. Degeneracy is shown to play an important role, esp ecially at large gate bias. Very good agreement with available experiments has been obtained, and yields a set of best-fit transport parameters. Our r esults underscore the dominance of interface roughness scattering, and demo nstrate that a parameterized model based on weak-perturbation, Born approxi mation theory can yield sufficiently accurate results. (C) 2000 American In stitute of Physics. [S0021-8979(00)08814-9].