The failure mechanism re-investigation Of ESD device on EPI wafer

The ESD failure mechanism of the EPI wafer device is reinvestigated, which is caused by the low substrate resistance induced transient current crowding. We also demonstrate that putting the ESD device in the deep-NWell (DNW) can effectively eliminate the low substrate resistance effect because the device in the DNW can be isolated from the P+ substrate. The DNW can not only improve the HBM and MM threshold voltages for EPI wafer device but also improve the CDM threshold voltage for EPI wafer and bulk wafer devices.