Practical aspects of the depletion etch method in high-voltage devices

In an earlier paper a new junction-termination geometry was described which was able to give near-ideal avalanche breakdown voltage in both plane and planar p-n junctions. The difficulty of the DEM (depletion etch method) was to achieve a precise etch depth which failure to achieve led to reduced effectiveness. In this paper the range of avalanche breakdown voltage is related to the accuracy of the depletion etch in a quanitative and rather general way so thatDelta V, the decrease in breakdown voltage below the ideal is related toDelta Y, the deviation in etch depth from the ideal, for any p-n junction.