Semiconductor light emitting device

#1. Field of the Invention

#The present invention relates to a semiconductor light emitting device including a light emitting layer in a semiconductor layer formed on a substrate.

#2. Description of Related Art

#FIG. 1 shows a schematic sectional view of a semiconductor light emitting device according to a preferred embodiment of the present invention.

#FIGS. 2A and 2B show graphical perspective views illustrating examples of an arrangement of a diffraction/scattering film provided in the semiconductor light emitting device.

#FIGS. 3A to 3J show schematic sectional views illustrating a method of manufacturing the semiconductor light emitting device illustrated in FIG. 1.

#A semiconductor light emitting device according to a preferred embodiment of the present invention includes a substrate, a semiconductor layer which is formed on the substrate and includes a light emitting layer, and a diffraction/scattering film, which is formed between the light emitting layer and the substrate, for diffracting or scattering light generated at the light emitting layer, the diffraction/scattering film having a side surface slanted with respect to a film thickness direction thereof and having a composition gradient in the film thickness direction.

#Light generated at the light emitting layer may be extracted from the device either from the substrate side or from the opposite side of the substrate. The diffraction/scattering film diffracts or scatters light generated at the light emitting layer, so as to reduce total reflection at an interface between the substrate and the semiconductor layer. This can improve the light extraction efficiency. More specifically, since the diffraction/scattering film has a side surface slanted with respect to the film thickness direction, the side surface can prompt diffraction/scattering of light. This contributes to improvement in the light extraction efficiency.

#The diffraction/scattering film has a gradient composition which is gradient in a film thickness direction. Therefore, in formation of the diffraction/scattering film by etching, the etching rate varies at respective portions in a film thickness direction. Therefore, a side surface of the diffraction/scattering film becomes slanted in accordance with the gradient composition. Accordingly, by controlling the gradient composition in the film thickness direction of the diffraction/scattering film, it is possible to control the slant of a side surface of the diffraction/scattering film. The gradient composition in the film thickness direction of the diffraction/scattering film can be controlled with high accuracy and with high reproducibility. As a result, it becomes possible to control the slant of a side surface of the diffraction/scattering film with high accuracy and with high reproducibility. This provides a semiconductor light emitting device having an arrangement which can achieve excellent light extraction efficiency with high reproducibility.