A case study of NMOS AC hot carrier injection lifetime improvement

The work presented here shows a series of engineering runs to improve the AC HCI lifetime for a 0.60 mum NMOS. The conventional method of increasing NLDD energy and reducing NLDD dose did not achieve significant improvement. The study concludes that tilting the NLDD implant, coupled with prolonging the NLDD anneal and increasing the Poly CD can improve the lifetime significantly. A short HCI test was performed to compare the response of different splits. Process simulation was also being performed to visualise variances in electrical field distribution associated with the differing splits.