Hot-Electron Substrate-Current Generation During Switching Transients

The characteristics of hot-electron substrate-current generation in n-channel MOSFET´s during switching transients of an inverter are studied. The amount of substrate current generated depends strongly on the loading and the input transition time (switching speed) of the inverter. Most circuit elements including inverters, source followers, and transfer gates have similar behaviors in transient substrate-current generation. An analytical model is proposed to calculate the substrate-current generation with various supply voltages and input transition times. This model not only establishes the relationship between dc and transient substrate-current measurements, but also serves as a useful tool in predicting circuit/device reliability during actual circuit operations.