Benefits of Nitrogen Co-Implantation on 28nm SRAM

We have successfully reduced threshold voltage variation by Nitrogen co-implantation. Doping profile is modulated through co-implantation of diffusion suppressor. The effects of implantation on device performance are investigated especially in terms of junction leakage. We have explored the possibility of Nitrogen dosage, energy and tilt angle in order to minimize junction leakage. With optimum combination, NMOS/SRAM Local variance is achieved ~2mV improvement accompanied with reduced leakage current.