Practical Design of 4H-SiC Superjunction Devices in the Presence of Charge Imbalance
In the ideal case, superjunction (SJ) drift regions theoretically exhibit a linear relationship between specific-on resistance Ron,sp and blocking voltage VBR, but this requires perfect charge balance between the alternating n and p pillars. If any degree of imbalance exists, the relationship becomes quadratic, similar to a conventional drift region, although with somewhat improved performance. In this work, we analyze superjunction drift regions in 4H-SiC under realistic degrees of charge imbalance and show that, with proper design, a reduction in specific on-resistance of 2~10x is possible as long as the imbalance remains less than ±20%.
Robert Stahlbush, Philip Neudeck, Anup Bhalla, Robert P. Devaty, Michael Dudley and Aivars Lelis
M. M. Alam et al., "Practical Design of 4H-SiC Superjunction Devices in the Presence of Charge Imbalance", Materials Science Forum, Vol. 924, pp. 563-567, 2018