Semiconductor light emitting device and method for manufacturing same
According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a light emitting portion, a first transparent conductive layer, and a second transparent conductive layer. The light emitting portion is provided between the first and second semiconductor layers. The second semiconductor layer is disposed between the first transparent conductive layer and the light emitting portion. The first transparent conductive layer includes oxygen. The second transparent conductive layer is provided between the second semiconductor layer and the first transparent conductive layer. The second transparent conductive layer has a refractive index higher than a refractive index of the first transparent conductive layer, and includes oxygen at a concentration higher than a concentration of oxygen included in the first transparent conductive layer.
1. A method for manufacturing a semiconductor light emitting device, comprising:
forming a transparent electrode including a lower transparent conductive film and an upper transparent conductive film on a semiconductor layer provided on a light emitting portion, including,
forming the lower transparent conductive film on the semiconductor layer provided on the light emitting portion by a vapor deposition method, said lower transparent conductive film being formed in an atmosphere free of oxygen and including an inert gas;
performing a first annealing of the lower transparent conductive film in an atmosphere including oxygen after forming the lower transparent conductive film;
forming the upper transparent conductive film on the lower transparent conductive film by a vapor deposition method in an atmosphere including oxygen after performing the first annealing; and
performing a second annealing in a first reduction atmosphere after the forming the upper transparent conductive film, the first reduction atmosphere including at least one of nitrogen and an inert gas, and the first reduction atmosphere not including oxygen.
2. The method according to claim 1 , wherein the forming the lower transparent conductive film includes forming the lower transparent conductive film by a sputtering method in an atmosphere including an inert gas, and the forming the upper transparent conductive film includes forming the upper transparent conductive film by a sputtering method in an atmosphere further including an inert gas.
3. The method according to claim 1 , further comprising performing a third annealing in a second reduction atmosphere after the performing the first annealing in the atmosphere including oxygen and before the forming the upper transparent conductive film, the second reduction atmosphere includes at least one of nitrogen and an inert gas, and the second reduction atmosphere not including oxygen.
4. The method according to claim 1 , wherein the forming the lower transparent conductive film includes forming the lower transparent conductive film by a sputtering method in an atmosphere without oxygen, and the forming the upper transparent conductive film includes forming the upper transparent conductive film by a sputtering method in an atmosphere including oxygen.
5. The method according to claim 1 , wherein the lower transparent conductive film is an ITO film, and the upper transparent conductive film is an ITO film.