ELECTRON-TRANSPORT CHARACTERISTICS OF GAN FOR HIGH-TEMPERATURE DEVICEMODELING

Monte Carlo simulations of electron transport based upon an analytical representation of the lowest conduction bands of bulk, wurtzite phase GaN are used to develop a set of transport parameters for devices wit h electron conduction in GaN. Analytic expressions for spherical, nonp arabolic conduction band valleys at the Gamma, U, M, and K symmetry po ints of the Brillouin zone are matched to experimental effective mass data and to a pseudopotential band structure. The low-field electron d rift mobility is calculated for temperatures in the range of 300-600 K and for ionized impurity concentrations between 10(16) and 10(18) cm( -3). Compensation effects on the mobility are also examined. Electron drift velocities for fields up to 500 kV/cm are calculated for the abo ve temperature range. To aid GaN device modeling, the drift mobility d ependences on ambient temperature, donor concentration, and compensati on ratio are expressed in analytic form with parameters determined fro m the Monte Carlo results. Analytic forms are also given for the peak drift velocity and for the field at which the velocity peak is reached as functions of temperature. (C) 1998 American Institute of Physics.