Study of Edge Effects in the Breakdown Process of p+ on n-bulk Silicon Diodes

The paper describes the role of the n+ edge implants in the breakdown process of p+ on n-bulk silicon diodes. Laboratory measurements and simulation studies are presented on a series of test structures aimed at an optimisation of the design in the edge region. The dependence of the breakdown voltage on the geometrical parameters of the devices is discussed in detail. Design rules are extracted for the use of n-wells along the scribe line to avoid surface conduction of current generated by the exposed edges. The effect of neutron irradiation has been studied up to a fluence 1.8*10^15 n/cm2.