Behavioural Modelling for Stability of CMOS SRAM Cells Subject to Random Discrete Doping

Channel random discrete doping (RDD), one of the main sources of MOSFET intrinsic parameter fluctuations, significantly affects the stability of CMOS SRAM. This paper describes a behavioural model for 35 nm CMOS technology SRAM cells with random discrete dopants using VHDL-AMS (Analogue and Mixed Signal). The static transfer characteristic (STC) is described in the VHDL-AMS model. Monte Carlo simulation results of the behavioural model are close to those at SPICE level. The VHDL-AMS model can predict the worst case STC behaviour for SRAM induced by RDD but also improves the simulation speed by five times compared to SPICE.