A SiC light-activated Darlington heterojunction transistor is proposed for anti-EMI (electromagnetic interference) applications, in which a monolithically integrated SiCGe/SiC pn heterojunction photodiode is employed to produce a light-induced base current for triggering the transistor. Performance of the proposed light-activated power switch was simulated using MEDICI tools. Feasibility of the proposal is confirmed by its good light-activation characteristics obtained from the simulation. The simulation also demonstrates that good I-V characteristics with a light-independent turn-on voltage knee of about 5 V may be achievable to the light-activated power switch has.