Theory of abnormal thyristor forward voltage behavior

The on-state current-voltage characteristic of thyristors is investigated by numerical simulation. For sufficiently high p-base concentration-as already known-an abrupt increase in on-state voltage is observed above a critical current density. Driving the device to higher currents results in a reduction of on-state voltage. Similar results are obtained for thyristor profiles with very shallow emitters. An analytic model that explains the described phenomena from first principles and leads to a simple criterion for current limiting in terms of Gummel numbers and carrier mobilities is presented