The reverse breakdown voltage (V B ) of p-i-n rectifiers fabricated on 4H-SiC was measured as a function of device active area, mesa length and metal overlap distance for diodes with SiO 2 passivated mesa edge termination. V B was inversely dependent on device area for the range 0.01-0.36 mm 2 , decreasing from ~-1030 to ~-730 V. The breakdown voltage was not dependent on mesa length and was maximized at ~5 μm metal overlap distance. The on/off ratio was ~10 4 at 3.5/-1000 V, with the power figure-of-merit V B 2 /R O N reaching values as high as 84.5 MWcm - 2 .