Microwave silicon carbide Schottky diodes

A silicon carbide (4H-SiC) Schottky barrier diode designed for high power and high frequency applications is investigated. Current and capacitance measurements show that a diode with a radius of 5 μm has a cutoff frequency of 91 GHz. A larger 4H-SiC Schottky diode with an anode radius of 50 μm is shown to handle a reverse voltage of 40 V, while having a series resistance of 2.5 Ω and a cutoff frequency of 10 GHz. Empirical formulas for the series resistance and capacitance as a function of anode radius are derived for vertical diodes with cylindrical symmetry on the specific epistructure used in this work