Improving gate oxide integrity in p/sup +/pMOSFET by using large grain size polysilicon gate

The effect of polysilicon grain size on the gate oxide integrity in p/sup +/pMOS devices was investigated by measuring the electrical characteristics of a MOS capacitor. Good gate oxide integrity was never obtained when using conventional polysilicon with a small (/spl sim/0.05 /spl mu/m) grain size. We report for the first time use of large (/spl sim/1.0 /spl mu/m) grain size polysilicon to solve this problem for gate oxide quality. Additionally, in large-grain-size polysilicon, the efficiency of boron activation was increased and boron diffusion through the gate oxide into the channel region was strongly suppressed. >