Theoretical study of RF-breakdown in bulk GaN and GaN MESFETs

RF-breakdown was studied in bulk GaN and in GaN MESFETs using a full band M onte Carlo simulator. It was found that in bulk materials, increasing the f requency of an applied PF field would result in a lower overall impact ioni zation rate and consequently lead to higher breakdown fields. It was also f ound that the RF-breakdown voltage of devices increases with increasing fre quency of the applied large signal RF excitation. The frequency dependence of RF-breakdown and the difference between RF and de-breakdown is explained based on the time response of the particle energy to the change in the app lied RF excitation.