A simplified model of short-channel MOSFET characteristics in the breakdown mode

When a short-channel MOSFET is driven into the avalanche-induced breakdown region, the drain current increases rapidly and usually shows a snapback characteristic. Both the substrate current and the current collected by a nearby reverse-biased p-n junction also increases with increasing drain current in this region of operation. All of these effects are associated with minority-carrier injection from the source junction into the substrate. A model for the drain I-V characteristics is proposed. Also presented is a related model incorporating conductivity modulation that predicts linear relationships between the substrate and the collection currents and the drain current in this region of operation. Experimental results agree well with the models.