Hot carrier degradation improvement on submicron NMOSFET in Bipolar-CMOS-DMOS (BCD) process

We report a systemic study of hot carrier degradation improvements on submicron NMOSFET in Bipolar-CMOS-DMOS (BCD) process. The electric parameters Vth and Idsat in N-Channel MOSFET of BCD process show negligible degradation, whereas Idlin and GM exhibit significant degradation. The interface trapped charge due to hot electron injection makes the image charges at surface of NLDD. The hot carrier effect can be significantly reduced or screened out through properly increasing NLDD surface concentration. Also Back-End-of Line (BEOL) process effects on hot carrier degradation have been studied. We demonstrate that BEOL especially with high-density-plasma (HDP-CVD) oxide deposition can significantly degrade device hot carrier performance. We show experimentally that using properly high refractive index (RI) SiN film or SiON film can reduce the BEOL effect on hot carrier performance.