SEMICONDUCTOR LASER DEVICE

摘要

PURPOSE:To prevent the failure of a laser device by a construction wherein an P-N junction is provided in the crystal portion other than the active layer of a semiconductor laser device, and the density of impurities in this junction is controlled to keep it at the prescribed value, so that an excessive current bypasses the active layer. CONSTITUTION:N-type InP12, In0.73Ga0.27As0.63P0.37 active layer 13, and P-type InP14, P-type In0.83Ga0.27As0.37P0.63 15 layers are epitaxially grown on the surface (100) of an N-type InP substrate. An SiO2 mask 21 is provided in the direction (110), and the surface is etched by a mixed liquid of bromine and methanol to form a belt layer for enclosing light on the substrate 11. Next, P-type InP19 and N-type InP20 layers are laminated successively according to the prescribed density and thickness. After removing the oxide film on the surface, a eutective Au-Sn is evaporated on it, and a eutectic Cr-Au is evaporated on the p layer 15 side to form an electrode. Then it is cleaved at a right angle to the belt layer to complete a laser device. Since P-N-P-N junction is formed by layers 14-20-19-11 on the side of the buried layer, the current and voltage characteristics have a negative resisting region, so that it prevents the device from being destroyed even when an excessive current flows.