Vertical cavity surface emitting device
A vertical cavity surface emitting device includes a substrate, a first multilayer film reflecting mirror, a first semiconductor layer having a first conductivity type, a light-emitting layer, a second semiconductor layer having a second conductivity type opposite of the first conductivity type, and having an upper surface with a projection, an insulating layer that covers the upper surface of the second semiconductor layer and has an opening that exposes the second semiconductor layer on the upper surface of the projection terminated on the upper surface of the projection of the second semiconductor layer, a transmissive electrode layer that covers the upper surface of the second semiconductor layer exposed from the opening of the insulating layer and is formed on the insulating layer, and a second multilayer film reflecting mirror formed on the transmissive electrode layer and constituting a resonator together with the first multilayer film reflecting mirror.
1. A vertical cavity surface emitting device comprising:
a substrate;
a first multilayer film reflecting mirror formed on the substrate;
a first semiconductor layer formed on the first multilayer film reflecting mirror, the first semiconductor layer having a first conductivity type;
a light-emitting layer formed on the first semiconductor layer;
a second semiconductor layer formed on the light-emitting layer, the second semiconductor layer having a second conductivity type opposite of the first conductivity type, and the second semiconductor layer having an upper surface with a projection;
an insulating layer that covers the upper surface of the second semiconductor layer, the insulating layer having an opening that exposes the second semiconductor layer on the upper surface of the projection terminated on the upper surface of the projection of the second semiconductor layer;
a transmissive electrode layer that covers the upper surface of the second semiconductor layer exposed from the opening of the insulating layer, the transmissive electrode layer being formed on the insulating layer; and
a second multilayer film reflecting mirror formed on the transmissive electrode layer, the second multilayer film reflecting mirror constituting a resonator together with the first multilayer film reflecting mirror,
wherein:
the second semiconductor layer has a ring-shaped recess on the upper surface, and
the projection of the second semiconductor layer is a part defined by an inner end portion of the recess.
2. The vertical cavity surface emitting device according to claim 1 , wherein:
the insulating layer has a refractive index lower than a refractive index of the second semiconductor layer, and
the projection of the second semiconductor layer has a height equal to or more than a layer thickness of the insulating layer.
3. The vertical cavity surface emitting device according to claim 1 , wherein:
the opening of the insulating layer has a side surface shape that narrows toward the second semiconductor layer, and
the second multilayer film reflecting mirror is formed on a region inside the opening of the insulating layer, and has an inclined region in which the multilayer films are inclined due to the side surface shape of the opening and stacked.
4. The vertical cavity surface emitting device according to claim 1 , wherein:
the projection of the second semiconductor layer has a tapered shape toward the transmissive electrode layer.
5. The vertical cavity surface emitting device according to claim 1 , wherein:
each of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer is made of a nitride-based semiconductor,
the insulating layer is made of SiO 2 ,
the first multilayer film reflecting mirror is a distributed bragg reflector made of a semiconductor material, and
the second multilayer film reflecting mirror is a distributed bragg reflector made of a dielectric material.