Impact of Dielectric Insulation and Protection Layers on 233 nm Far-UVC LEDs

This letter investigates the effect of dielectric insulation or protection layers such as SiO ${}_{\mathbf {2}}$ and SiN ${}_{\mathbf {x}}$ on the performance and reliability of 233 nm far-UVC LEDs. The study includes the effect of n-contact annealing of chips with these layers. Results show that introducing a protection of the p-GaN surface and mesa edges by SiO ${}_{\mathbf {2}}$ and combining it with an insulation by SiN ${}_{\mathbf {x}}$ enhances the device performance. LEDs with a SiO ${}_{\mathbf {2}}$ protection layer that undergoes an n-contact annealing at $700~^{\circ }$ C offer minimum leakage and degradation.