4H-SiC p(+)-n-n(+) Zener diodes having avalanche breakdown voltages of about 300 V and Low dynamic impedance were fabricated and characterized at continuos and pulsed avalanche currents. The diodes were capable of operating at de currents up to 60 mA corresponding to a power of 18 W. They exhibited a value of dynamic impedance of 170 Omega at a test current of IO mA, a leakage current of 60 nA at 230 V and a positive temperature coefficient of breakdown voltage of 3.10(-4)K(-1).