Epitaxial Design of a Direct Optically Controlled GaAs/AlGaAs-Based Heterostructure Lateral Superjunction Power Device for Fast Repetitive Switching

We outlined the epitaxial design methodology for a novel compound-semiconductor-based optically controlled power device for fast repetitive switching frequency. The proposed structure features gallium arsenide (GaAs/AlGaAs) lateral heterostructure with charge-balancing superjunction layers to make the breakdown voltage of the device independent of doping of the photo-absorbing GaAs active layer and linearly dependent on the lateral length. This structure also features parallel plate like p-n junction, which reduces local electric-field crowding and supports higher reverse bias during off-state. We show that the use of lattice-matched wider bandgap AlGaAs helps to achieve superjunction charge balancing without having any effect on switching performance of the device. We also show that the particular processing methodology (ion implantation over zinc diffusion) helps in improving the breakdown-voltage capability of the device