Demonstration of a simple and efficient design methodology for
high-voltage floating field limiting ring in SiC power devices
Abstract
In this letter, we proposed and experimentally demonstrated a simple and
efficient design method for high-voltage Floating Field Ring (FFR).
Three floating FFRs is firstly used to determine the influence of rings’
distance (d) on the voltage drops of the highest voltage to second ring
(Vn+1) and the second to the first ring (Vn). Then, two voltage curves
(curve for Vn+1 and Vn) based on d are drawn. Then, for a target
breakdown voltage, by iteration between the curves for Vn+1 and Vn,
number of FFRs and corresponding distances can be found. Based on this
method, an 8.0 kV PN diode with 110 FFRs is designed and fabricated. The
measured breakdown voltage is 7840 V, which reaches 93% of the designed
value. This method provides a simple and efficient design for
high-voltage SiC devices, especially for ultra-high voltage applications
where the number of rings exceeds dozens.
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