Electron Mobility Calculations and Scattering Effects in GaN Compound Semiconductor

Compound semiconductors allow processing in electronic devices much faster than silicon-based devices since electrons can travel much faster than their counterparts in silicononly devices. Electron mobility for n-GaN compound semiconductor is calculated using simulation via relaxation time at different temperatures (up to 400 K) and different doping concentrations considering four elastic scattering mechanisms; namely: neutral impurity-, ionized impurity-, piezoelectric- and acoustic phonon-scattering. It is found that electron mobility of GaN increases as temperature increases for ionized impurity scattering, but it decreases for acoustic deformation and piezoelectric scatterings; while neutral impurity scattering was not affected by temperature changes. At higher temperatures, mobility due to piezoelectric scattering approaches that of deformation scattering and can be neglected. Mobility, at low temperatures, decreases with increasing doping concentrations. At room temperature, mobility also decreases as the n-GaN becomes increasingly doped most likely explained by massive ionized impurity scattering which restricts electron mobility. The low-field mobility of electrons generally decreases when temperature increases. The obtained results are compared with that from the literature exhibiting very good agreements.