A comprehensive study of polysilicon resistors for CMOS ULSI applications

摘要

The characteristics of polysilicon resistors for CMOS ULSI applications have been investigated. Based on the presented sub-quarter micron CMOS borderless contact, both n~+ and p~+ polysilicon resistors with Ti- and Co-silicide self-aligned process are used at the ends of each resistor. A simple and useful model is proposed to analyse and calculate some important parameters of polysilicon resistors including electrical delta W(ΔW), interface resistance R_(interface), and pure sheet resistance R_(pure). Furthermore, the characteristics of voltage-coefficient resistor, temperature-coefficient resistor, and resistor mismatching are also studied. An interesting sine-wave voltage-dependent characteristic due to the strong relation to the R_(interface) has been modelled in this paper. This approach can substantially help engineers in designing and fabricating the precise polysilicon resistors in sub-quarter micron CMOS ULSI technology.