Enhancing the robustness of a multiple floating field-limiting ring termination by introducing a buffer layer

A planar multiple floating field-limiting ring structure, designed for above 600V blocking capability, is analyzed in this work. We have proven by simulation and experiment that adding a well designed buffer layer in the epi-substrate region counteracts on the drop in electric field which is due to the space charge limited current and as such the buffer enhances the robustness towards reverse voltage biasing.