Vertical cavity surface emitting device
A vertical cavity surface emitting device includes a substrate, a first multilayer film reflecting mirror, a light-emitting structure layer with a light-emitting layer, and a second multilayer film reflecting mirror. The second multilayer film reflecting mirror constitutes a resonator between the first and second multilayer film reflecting mirrors. The second multilayer film reflecting mirror includes a first multilayer film, an intermediate film, and a second multilayer film. The first and second multilayer films have low refractive index films and high refractive index films that are alternately stacked. The intermediate film covers an upper surface of the first multilayer film and film has a translucency to a light emitted from the light-emitting layer. The second multilayer film partially covers an upper surface of the intermediate film. The intermediate film has a film thickness based on ½ of a wavelength inside the intermediate film of light emitted from the light-emitting layer.
1. A vertical cavity surface emitting device comprising:
a substrate;
a first multilayer film reflecting mirror formed on the substrate;
a light-emitting structure layer formed on the first multilayer film reflecting mirror, the light-emitting structure layer including a light-emitting layer; and
a second multilayer film reflecting mirror formed on the light-emitting structure layer, the second multilayer film reflecting mirror constituting a resonator between the first multilayer film reflecting mirror and the second multilayer film reflecting mirror,
wherein:
the second multilayer film reflecting mirror includes a first multilayer film, an intermediate film, and a second multilayer film, the first multilayer film having low refractive index films made of a low refractive index material and high refractive index films made of a high refractive index material having a refractive index higher than a refractive index of the low refractive index material, the low refractive index films and the high refractive index films being alternately stacked, the intermediate film covering an upper surface of the first multilayer film, the intermediate film having a translucency to a light emitted from the light-emitting layer, the second multilayer film being formed to partially cover an upper surface of the intermediate film, the second multilayer film having the low refractive index films made of the low refractive index material and the high refractive index films made of the high refractive index material, and the low refractive index films and the high refractive index films being alternately stacked,
the intermediate film has a film thickness based on ½ of a wavelength inside the intermediate film of a light emitted from the light-emitting layer,
an upper surface of the second multilayer film and an area on the upper surface of the intermediate film where the second multilayer film is not formed are optically exposed, and
the high refractive index films, the low refractive index films, and the intermediate film are made of a dielectric film.
2. The vertical cavity surface emitting device according to claim 1 , wherein:
the first multilayer film has a side closest to the substrate on which a low refractive index film is disposed and the first multilayer film has a side closest to the intermediate film on which a first thin film high refractive index film made of the high refractive index material is disposed, the first thin film high refractive index film having a film thickness smaller than a film thickness of the high refractive index film,
the second multilayer film has a side closest to an upper surface thereof on which a low refractive index film is disposed and the second multilayer film has a side closest to the intermediate film on which a second thin film high refractive index film made of the high refractive index material is disposed, the second thin film high refractive index film having a film thickness smaller than a film thickness of the high refractive index film, and
the second multilayer film and the intermediate film have upper surfaces covered with a metallic film.
3. The vertical cavity surface emitting device according to claim 2 , wherein:
the second multilayer film has five each of the low refractive index films and the high refractive index films, and the thin film high refractive index film,
the low refractive index films and the high refractive index films in the first and second multilayer films have a film thickness based on ¼ of a wavelength in each of the low refractive index films and the high refractive index films of the light emitted from the light-emitting layer, and
the first and second thin film high refractive index films in the first and second multilayer films have a film thickness based on ⅛ of a wavelength inside the first and second thin film high refractive index films of the light emitted from the light-emitting layer.
4. The vertical cavity surface emitting device according to claim 1 , wherein:
the first multilayer film has a side closest to the substrate on which the low refractive index film is disposed, and the first multilayer film has a side closest to the intermediate film side on which the low refractive index film is disposed, and
the second multilayer film has a side closest to an upper surface thereof on which the low refractive index film is disposed, and the second multilayer film has a side closest to the intermediate film on which the high refractive index film is disposed.
5. The vertical cavity surface emitting device according to claim 4 , wherein:
the second multilayer film has five each of the low refractive index films and the high refractive index films, and
the low refractive index films and the high refractive index films in the first and second multilayer films have a film thickness based on ¼ of a wavelength in each of the low refractive index films and the high refractive index films of the light emitted from the light-emitting layer.
6. The vertical cavity surface emitting device according to claim 1 , wherein the second multilayer film is formed into a ring shape on the upper surface of the intermediate film.
7. The vertical cavity surface emitting device according to claim 1 , wherein the intermediate film has an etching rate smaller than etching rates of the low refractive index films and the high refractive index films of the second multilayer film.
8. The vertical cavity surface emitting device according to claim 1 , wherein the intermediate film is made of an Al 2 O 3 film or an AlN film.
9. The vertical cavity surface emitting device according to claim 1 , wherein a mirror loss in a region including the area on the upper surface of the intermediate film where the second multilayer film is not formed is larger than a mirror loss in a region including the upper surface of the second multilayer film.
10. The vertical cavity surface emitting device according to claim 1 , wherein:
the light-emitting structure layer has a p-type semiconductor layer on the light-emitting layer,
the p-type semiconductor layer has a projection on an upper surface of the p-type semiconductor layer, and
an insulating layer is formed on the upper surface of the p-type semiconductor layer except the projection.