Multi-cell effects during unclamped inductive switching of Power MOSFETs

In this paper, we describe the crucial dependence of avalanche behavior on epitaxial layer thickness and gate resistance during undamped inductive switching (TJIS) especially for high currents for power MOSFET devices employing field-plate compensation in the drift region. All transient simulations were performed using Medici´s mixed-mode simulation approach including self-heating. A higher epitaxial layer thickness eventually resulted in a higher avalanche ruggedness but also in higher on-state resistance. Thus, a trade-off exists.