Abstract: A novel light-activated Darlington heterojuntion transistor power switch which is made of narrow bandgap ternary SiCGe alloys and SiC is proposed in which SiCGe/SiC pn heterojunction is employed to produce a base current by means of optical illumination.By using two-dimensional numerical simulation,performance of the novel light-activated power switch is simulated.It is shown that the light-activated device has very good switching characteristics for a infrared triggering light,and the forward voltage drop is about 4.5V during condition of saturation turn-on,and the switch is well suited for high light power.

Key words: SiC, light-activated Darlington transistor, heterojuntion, power switch