The effect of P-type doping of polysilicon PMOS applications

This paper presents the effect of p-type doping of polysilicon for BF₂+, boron, gallium and indium at various doping concentration from 10¹¹ to 10²⁰ (atoms/cm³) for PMOS device using SILVACO TCAD (Technology Computer Aided Design) software. It is seen that the effect of p-type doping at certain level of dose significantly effects the performance of the PMOS device. The threshold voltage of polysilicon obtain from ID-VGS curve was analyzed. The results show that BF₂+ at dose 10¹⁴ to 10¹⁹ (atoms/cm³) and gallium at dose 10¹³ to 10²⁰ (atoms/cm³), both are giving the better characteristics of the PMOS and give almost the same threshold voltage at 1.0V to 1.3V, but the most effective for both doping are concentration at dose 10¹⁴ (atoms/cm³). The resistivity of the polysilicon is gradually decreased as a concentration of doping increase, while the conductivity is reciprocal of the resistivity. Furthermore, the smaller leakage current is wanted to achieve a better device, where the BF₂+ and gallium doping has result less leakage current.