Fast power diode e.g. Schottky or PIN-epitaxial diode - uses PNN with doping of P region adjusted to give optimum switching and blocking characteristics

摘要

The cross-section of the structure of a fast power diode has a heavily doped very thick n+ substrate region (1), a high resistance highly doped very thin n- middle region (2) and a very thin epitaxial p-region (3). The doping of the second outer layer (3) is chosen to give no emission of majority carriers in the forward direction. Preferably, the doping concentration of region (3) is 5 x 10 to the power 14 - 5 x 10 to the power 16 cm to the power (-3) with a thickness of 3-20 micrometre. Heavy metal doping provides recombination centres to give negligible carrier lifetime. ADVANTAGE - Negligible switching loss and high blocking voltage.