An Equivalent Circuit of Hot Carrier Injection in Short-channel N-MOSFET

Abstract

This paper presented an equivalent circuit based on a 65nm NMOS model to simulate the hot carrier injection (HCI) effect. Under HCI effect, many electrical characteristics such as threshold voltage, trans conductance, drain-source current, gate leakage current, etc, will be obviously changed during a long period of operation time and under different voltage stress. The method of directly modifying SPICE model to simulate HCI effect is complex, and it may lead to non-convergence. Based on an NMOSFET model of a 65nm CMOS PDK, adding some common electrical components and arithmetic units to form an equivalent circuit is a practical way. This model has 4 input parameters, such as width of gate (W), length of gate (L), environment temperature (Temp), operation period (Year). The voltage stress of drain source, drain-gate, gate-source are also considered in this model. The simulation results show that the electrical performance of NMOS transistor under HCI is fitted many measured data of published papers. This equivalent circuit model can be used in the integrated circuit to estimate the effect of HCI.