High voltage photoconductive switches using semi-insulating, vanadium doped 6H-SiC

SiC manufacturers are continually improving the purity of their wafers, however, interband impurities, while detrimental in many applications, can be useful in the operation of photoconductive switches. Compact, high-voltage photoconductive switches were fabricated using c-plane; vanadium doped 6H-SiC obtained from II-VI, Inc. This material incorporates a large amount of interband impurities that are compensated by the vanadium amphoteric, but at present is only available as c-plane wafers. In order to avoid micropipe defects, lateral switches were fabricated to allow validation of material simulations. Low resistivity contacts were formed on the semi-insulating material and a high-voltage encapsulant increases the surface flashover potential of the switch. Material characteristics were determined and switch parameters were simulated with comparisons made to experimental data.