Improved thermal characteristic of InGaN laser diodes with AlGaN ridge passivation layer

The effect of thermal conductivity of ridge passivation layer materials on the thermal characteristics of InGaN-based laser diodes (LDs) emitting at a wavelength around 405 nm is investigated. For the SiO₂ and AlGaN passivation layers, junction temperature and thermal resistance of LDs are compared in the p-side down configuration. More than 30% reduction in thermal resistance is achieved when SiO₂ is replaced with AlGaN as the ridge passivation material, which is attributed to the high thermal conductivity of the AlGaN layer.