Subsurface breakdown devices

In the past, avalanche breakdown has been avoided in junctions for which there are requirements for stable low reverse bias leakage and/or stable minority carrier lifetime, It is well known that breaking down the emitter-base junction of a conventional planar bipolar transistor leads to a reduction of current gain and an increase in junction leakage. Recent studies all indicate that such degradation is due to the creation of interface states at the Si-SiO2interface and that degradation can be avoided if the breakdown is forced to occur away from the interface.