4H-SiC buried gate field controlled thyristor

Abstract

Commercial field controlled thyristors (FCT) offer much higher speeds, better dI/dt and dV/dt capabilities, lower on-state voltage drop and more stable high temperature operation than GTOs. They show higher reliability than an MOS based power device. This paper reports the fabrication of the first 4H-SiC FCT using a novel buried gate structure that gives a high DC blocking gain (cathode voltage to gate voltage during off-state). This gate structure was fabricated with a p-type epitaxial layer grown over an n/sup +/ ion implanted gate mesh. While the gate width (L/sub g/) should be as small as possible for a low on-state voltage drop, it should be sufficiently large to prevent debiasing of the gate fingers. Five different gate designs with various channel lengths and implanted gate widths were implemented to analyze the trade-off between on-state voltage drop and blocking voltage.