Influence of MOS transistor gate oxide breakdown on circuit performance

MOS transistor gate oxide breakdown is a common failure mechanism which needs to be understood in terms of its impact on circuit performance. Studies have shown that post MOS transistor gate oxide breakdown forms a phosphorous diffusion path in the gate oxide. This diffusion path originates from the phosphorous doped polysilicon gate. The effect of p- and n-channel gate oxide breakdown on the functionality of a four-inverter chain circuit is studied through SPICE simulations. Gate-to-drain oxide breakdown of either p- or n-channel transistors was found to significantly degrade overall circuit performance.