Monte Carlo investigation of current voltage and avalanche noise in GaN double-drift impact diodes

By Monte Carlo simulations, we investigate the current voltage characteristics and the current noise in GaN homojunction double-drift impact avalanche diodes. We have found that a suppression of avalanche noise from the standard excess noise factor starts when the dielectric relaxation time becomes comparable or less than the carrier transit time. The suppression reaches values down to three orders of magnitude when the current approaches the electrical breakdown regime. The negative feedback between fluctuations of the space charge and of the number of electron-hole pairs generated under avalanche conditions is found to be responsible for this giant suppression of noise.