Effect of Impact-Ionization-Generated Holes on the Breakdown Mechanism in LDMOS Devices

The breakdown mechanism in LDMOS devices with high resistive drift region sustaining high-voltage applications is analyzed and explained. Holes generated by the impact-ionization in the drift region are found to hinder the formation of the breakdown condition by increasing the potential underneath the gate-overlap region. This mechanism is modeled and implemented into the compact model HiSIM_HV for circuit simulation. Good agreement of simulated characteristics with 2D-device simulation results has been achieved.