Diffused spiral junction termination structure: modeling and realization

An innovative junction termination structure for efficient improvement of planar pn junction breakdown properties is studied. It is composed of a high-resistivity layer, connected to the anode junction and winding around it in a spiral fashion. Leakage current through the diffused resistor results in the spread of potential along the spiral resistor and reduction of high electric field at the junction curvature region. An optimized design with decaying spiral width and increasing spacing between the spiral turns leads to close to ideal breakdown voltages as confirmed by device modeling as well as experimental results.