Improving the Performance of Superjunction Devices Having Fixed Charge in Isolation and Termination Oxide Layers

This paper concerns superjunctions which employ oxide layers for isolating n- and p-pillars and in terminating the device. In our earlier work, we pointed out that oxide fixed charges significantly reduce the breakdown voltage of such devices. In this paper, we discuss various techniques in compensating the effects of oxide fixed charge so as to design such a device having the minimum specific on-resistance for a given breakdown voltage. The techniques include doping modification and reduction in the widths of terminating pillars and nonconducting pillars in the on-state. We also analyze the relative contributions of oxide fixed charges and doping-related charge imbalance to breakdown reduction to highlight the significance of oxide fixed charges.