THE IMPACT OF NITROGEN IMPLANTATION INTO HIGHLY DOPED POLYSILICON GATES FOR HIGHLY RELIABLE AND HIGH-PERFORMANCE SUB-QUARTER-MICRON DUAL-GATE COMPLEMENTARY METAL-OXIDE-SEMICONDUCTOR

We studied the effects of nitrogen implantation into highly doped poly silicon gates in detail. It was found that highly arsenic-doped polysi licon gates caused degradation of gate oxide films and highly boron-do ped polysilicon gates resulted in a shift of threshold voltage by boro n penetration. Nitrogen implantation into polysilicon gates can effect ively overcome these problems. The nitrogen implanted into the polysil icon gate is segregated into the gate oxide film during heat treatment after implantation. The nitrogen in the gate oxide film can act as a barrier layer for boron penetration and reduce the random failures of gate oxide films under highly doped polysilicon gates. Moreover, the h ot carrier resistance can also be improved by nitrogen implantation. H ighly reliable and high-performance dual-gate Complementary metal oxid e semiconductor (CMOS) can be realized by the highly doped gate and th e nitrogen implantation technique.