Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperature mask has been demonstrated. Nomarski optical microscope and scanning electron microscope (SEM) were used to characterize selective growth of SiC. In addition, 250 mu m square shaped p-n junction diodes by selective n type epitaxial growth on p type epi layer were fabricated. The refilled fingers with different width were designed to vary the periphery/area (P/A) ratio. The effects of P/A ratio on the current-voltage (J-V) characteristics have been investigated. The ideality factor extracted from J-V characteristics is approximate to 2 at temperature range of 25-275 degrees C, which indicates that the Shockley-Read-Hall recombination is the dominant mechanism in the conduction region. The reverse leakage current did not show dependence on P/A ratio for trench refilled diodes. The room temperature reverse leakage current density at 100V is less than 3.5x10(-7) A/cm(2) for all diodes. Also, the reverse leakage current did not increase significantly with temperature up to 275 degrees C. The breakdown voltages measured at room temperature are about 450V and 400V for diodes without and with fingers, respectively.