ESD Robustness of 40-V CMOS Devices With/Without Drift Implant

The dependences of device structures and layout parameters on ESD robustness in a 40-V CMOS process have been investigated in silicon chips. From the experimental results, the high-voltage (HV) MOSFETs without drift implant in the drain region have better TLP-measured It2 and ESD robustness than those with drift implant in the drain region. Furthermore, the It2 and ESD level of HV MOSFETs can be increased as the layout spacing from the drain diffusion to polygate is increased