A double etched profile for improved breakdown voltage in pn-junctions: theory and practice

A poorly designed geometry at the junction edge can severely limit the blocking capability of high voltage pn-junctions. The work presented involves the design of a double groove where we attempt to spread the electric field along the plateau region formed between two grooves. This leads to reduced surface field values, giving enhanced voltage breakdown. Although the value of the peak electric field is dependent on the depth of the shallow etch, it is shown that the allowable tolerance in this depth is approximately 10%, making this design a viable proposition for production.