An Analytical Model for Weak Avalanche Induced Kink Effect of PDSOI nMOSFETs

Silicon-on-insulator (SOI) devices and circuits are widely used in semiconductor industry for its superior natures on integration density, isolations degree. Inefficient body contact of partially-depleted SOI (PDSOI) devices cannot evacuate excess carriers which transported from the weak avalanche multiplication of pinch-off region at high drain voltage bias. These accumulated carriers elevate the internal body potential and trigger electrical effects namely the body bias effect of threshold voltage and the turn-on of parasitic bipolar junction transistor (BJT). A comprehensive analytical model which include all these mechanisms are proposed to describe this kink effect. This model is constructed by an equivalent circuit and five strong nonlinearly coupled equations to describe the electrical behaviors. To solve these equations, a C++ Qt-based graphical interface software is developed for the parameter extraction of the model. The fixed point iteration algorithm are adopted for the solution of equations. The effectiveness and accuracy of this model are verified by the T-gate shaped PDSOI nMOSFETs of 130 nm manufacturing process node. It can predict the electrical behaviors of kink effect. This is meaningful for the circuit simulation of PDSOI platform.