Effect of arsenic and phosphorus doping on polysilicon resistor noise and TCR

Abstract

Flicker (1/f) noise and TCR are compared for arsenic- and phosphorus-doped polysilicon in a 0.18 μm CMOS base technology. Resistors implanted with arsenic exhibit about 4 times higher noise than with phosphorus at the same dose and thermal budget. The TCR of arsenic-doped polysilicon is negative, near -1065 ppm/K, while that of phosphorus-doped resistors positive, about + 590 ppm/K. The mismatch of N-channel MOSFETs with arsenic-doped gates is about 40% lower than with phosphorus gates. The results are attributed to the difference in grain-size and dopant segregation. The difference in grain size is confirmed by TEM and SEM micrographs.