Power bipolar transistors with a fast recovery integrated diode

We have integrated a fast recovery diode in the structure of a power bipolar transistor. This integral diode is physically connected between the emitter and the collector of the transistor and can be used as a free-wheeling diode in power switches. Selective reduction of the minority carrier lifetime in the region of the diode was realized by Pt implantation in the diode area followed by an optimized thermal process that limits the lateral diffusion of the metal atoms. Using this metal doping a reduction by a factor of 10 of the reverse recovery charges of the integrated diode is obtained without affecting significantly the current carrying capability of the transistor.