An Equivalent Circuit Model for Negative Bias Temperature Instability Effect in 65nm PMOS

Abstract

This paper introduces an equivalent circuit modelfor Negative Bias Temperature Instability (NBTI) effect in 65nm PMOS. Comparing with other models based on physical effect mechanism, the method of equivalent circuit model is more practical. Based on PMOS model of an existing 65nm CMOS PDK, several common electrical components and arithmetic units are utilized to form an equivalent circuit. The components include resistor, voltage source, current source, voltage-controlled voltage source, voltage controlled current source, current controlled current source, adder, multiplier, etc. Four input parameters, such as width of gate (W), length of gate (L), ambient temperature (temp), operation period (t), are included in this equivalent circuit model. This model also considered the voltage stress of drain-source, drain-gate, and gate-source. The simulation results show that the electrical performance of PMOS transistor under NBTI is fitted the measured data of many published papers. The equivalent circuit model will be utilized for long period reliability integrated circuit design in the future.