A new 600V PT-IGBT for the improved avalanche energy by employing the floating p-well

A new IGBT employing a floating p-well, which improves the avalanche energy, is proposed and verified using the 2D numerical simulation. By implementing the floating p-well, the peak point of impact ionization moves from the surface under the gate to the bottom of the p-well so that the hole current flows vertically through the bottom of the p-well under the unclamped inductive switching (UIS). Hence, the avalanche capability can be significantly improved by the reduction of the hole current beneath the n+ emitter. Also, the saturation voltage of the proposed device can be comparable to that of the conventional device by adjusting the thickness of the n-epitaxial layer.