Enhancement of Blocking Voltage in GaN HEMT Using Stacked Passivation Layer

A stacked passivation pattern for GaN based HEMT has been proposed. The performance of the proposed device is benchmarked with conventional device. The analysis and simulation of the HEMT is carried out using Technology Computer Aided Design (TCAD) physical simulator. The simulation is calibrated using various physics based models. Impact of stacked passivation on electric field and breakdown voltage has been investigated and demonstrated. In contrast to conventional HEMT, it is found that the proposed device is effective in spreading electric field. It is observed that the breakdown voltage of proposed HEMT with stacked passivation is higher than conventional HEMT by 15%. The enhancement in breakdown voltage is well corroborated using impact ionization rate and off-state current density.