ESD Immunity Impacts of the Drain-Side Heterojunction Device Addition in HV 60 V n/pLDMOS Devices

A heterojunction-Schottky diode has a low forward-voltage drop and a fast switching feature. Therefore, in this paper, the drain side heavily doped region was removed and equivalently added a heterojunction device in 60 V n/pLDMOS devices, and evaluating its ability of ESD immunity. From the TLP measure result, the optimized secondary breakdown current of nLDMOS can be increased from 2.35 A to 3.85 A (improved 63.8%); the optimized secondary breakdown current of pLDMOS can be increased from 0.78 A to 2.83 A (improved 263%). It can be found that from removing the drain-side heavily doped region in LDMOS, LDMOS devices are equivalent with a large series heterojunction device, they are indeed very effective in improving the ESD reliability of n/pLDMOS devices.