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In this letter we report on the fabrication and initial electrical characterization of the first silicon carbide diodes to demonstrate rectification to reverse voltages in excess of 2000 V at room temperature. The mesa structured 6H-SiC p+n junction diodes were fabricated in 6H-SiC epilayers grown by atmospheric pressure chemical vapor deposition on commercially available 6H-SiC wafers. The devices were characterized while immersed in FluorinertTM to prevent arcing which occurs when air breaks down under high electric fields. The simple nonoptimized diodes, whose device areas ranged from 7×10−6 to 4×10−4 cm2, exhibited a 2000 V functional device yield in excess of 50%.

Reactive ion etching (RIE) of silicon carbide (SiC) to depths ranging from 10 µm to more than 100 µm is required for the fabrication of SiC power electronics and SiC MEMS. A deep RIE process using an inductively coupled plasma (ICP) etch system has been developed which provides anisotropic etch profiles and smooth etched surfaces, a high rate (3000 Å/min), and a high selectivity (80:1) to the etch mask. An etch depth of 100 µm is demonstrated.

A chemical vapor deposition (CVD) process has been used to produce device structures of n-and p-type 6H-SiC epitaxial layers on commercially produced single-crystal 6H-SiC wafers. Mesa-style p-n junction diodes were successfully fabricated from these device structures using reactive ion etching, oxide passivation, and electrical contact metallization techniques. When tested in air, the 6H-SiC diodes displayed excellent rectification characteristics up to the highest temperature tested, 600 °C. To observe avalanche breakdown of the p-n junction diodes, testing under a high-electrical-strength liquid was necessary. The avalanche breakdown voltage was 1000 V representing the highest reverse breakdown voltage to be reported for any CVD-grown SiC diode.