화학공학소재연구정보센터
Materials Science Forum, Vol.389-3, 1243-1246, 2002
Simulation study of a novel current-limiting device: A vertical alpha-SiC JFET - Controlled current limiter
Considering fault current limiters for serial protection, a lot of structures exist, from regulation to other complex systems such as circuit breakers, mechanical switches or more conventional system : fuses. Up to now, only few semiconductor current limiter structures were described in papers [I]. Although Current Regulative Diode components exist [2, 3], the voltage and current capabilities (V-BR=100 V, I-max=10 mA), do not allow to use them in power systems. A comparison of a silicon Current Regulative Diode (CRD) and an equivalent SiC one demonstrates the thermal and electrical limitations of silicon. This paper deals with a novel bi-directional current limiter structure based on a vertical alpha-SiC VJFET, with both buried gate and source. This device was designed for short circuit protections. Simulations were performed with ISE-TCAD [4] to evaluate static and transient electrical characteristics of the VJFET, according to several specifications : voltage capability, current rating, time during which the device can sustain a short circuit. Simulations allow geometrical design and doping profile estimation as well as the technological process to realize such a component. Both 6H and 4H-SiC Controlled Current Limiter (CCL) have been realized. Electrical characterizations of fabricated devices underline the limiting effect and the command ability.