Leakage current voltage dependence and performance of power semiconductor devices in the breakdown (avalanche) region

A maximum permissible working voltage below the breakdown region of electrical characteristic is specified in the data sheets of many devices. Operation without risk of failure above the specified value of working voltage reaching the breakdown region is not possible It would be beneficial that high voltage devices to operate for short time in the breakdown region of electrical characteristic without risk of failure. It is shown that un-controlled voltage dependence of the leakage current flowing at the junction periphery can be a limitation for reliable operation in the breakdown region of electrical characteristic. Typical electrical characteristics are presented from an investigation performed on commercial devices available at this time. For most of high voltage diodes, the reverse leakage current manifests linear voltage dependence up to some applied voltage and then deviation from this takes place. A round knee of reverse electrical characteristic can be exhibited up to apparent vertical breakdown region. The voltage of the breakdown region can be significantly lower than the value corresponding to the avalanche breakdown occurring in the junction bulk. In the case of controlled - avalanche diodes, linear voltage dependence of reverse current is exhibited up to a sharp knee of the electrical characteristic caused by avalanche charge carriers multiplication in the junction bulk. In such a situation operation in the breakdown region without risk of failure is possible in specified conditions with absorption of high surge energy. For devices with round knee of electrical characteristic, failure can take place when performing in the breakdown region at low absorption energy. Better control on the level and voltage dependence of the leakage current of PN junctions from commercial devices can lead to performance improvement at operation in the breakdown region.