A novel high power optothyristor based on AlGaAs/GaAs for pulsed power-switching applications

Double-side molecular beam epitaxial growth on a thick LEC-grown semi-insulating (SI) GaAs wafer has been used to demonstrate a novel high power optothyristor for pulsed power-switching applications. The optothyristor has a P⁺N-SI-PN⁺ thyristor-like structure with the capital P and N standing for the wider bandgap optical window material, AlGaAs, and the SI standing for a 650 μm SI-GaAs substrate. With the “insertion” of the SI-GaAs bulk material into the conventional P⁺NPN⁺ thyristor structure and the use of wider bandgap AlGaAs, the device has achieved a record high performance compared to the existing GaAs or AlGaAs/GaAs based epitaxial thyristors. The performance of the optothyristors under forward bias has been characterized, including 1) the low field dynamic current-voltage characteristics to show post-triggering carrier injections. 2) the switched-current waveforms with varying device blocking voltage and from which the turn-on speed di/dt is determined, and 3) the dependence of the switched-current amplitude on the laser triggering position