Semiconductor laser device

摘要

A semiconductor laser device generates blue-violet light with an emission wavelength of 400 to 410 nm. The device includes an n-type group III nitride semiconductor layer, an active layer laminated on the n-type semiconductor layer and having an InGaN quantum well layer, a p-type group III nitride semiconductor layer laminated on the active layer, and a transparent electrode contacting the p-type semiconductor layer and serving as a clad. The n-type semiconductor layer includes an n-type clad layer and an n-type guide layer disposed between the clad layer and the active layer. The guide layer includes a superlattice layer in which an InGaN layer and an AlxGa1-xN layer (0≦X<1) are laminated periodically, the superlattice layer contacting the active layer and having an average refractive index of 2.6 or lower. The In composition of the InGaN layer is lower than that of the InGaN quantum well layer.

主权项

1. A semiconductor laser device for generating blue-violet light with an emission wavelength of 400 nm to 410 nm, comprising:
an n-type group III nitride semiconductor layer including
an n-type clad layer, andan n-type guide layer comprising a superlattice layer; an active layer laminated on the n-type group III nitride semiconductor layer and having an InGaN quantum well layer; a p-type group III nitride semiconductor layer laminated on the active layer, the p-type group III nitride semiconductor layer including
a p-type guide layer having a flat surface, anda p-type contact layer having an impurity concentration higher than an impurity concentration of the p-type guide layer; a transparent electrode in contact with the p-type group III nitride semiconductor layer, the transparent electrode serving as a clad; and an insulating film disposed between the p-type guide layer and the transparent electrode, the insulating film having a flat surface and an opening penetrating through the insulating film so as to expose the flat surface of the p-type guide layer through the opening, wherein the p-type guide layer is disposed between the active layer and the transparent electrode, the p-type contact layer is disposed between the p-type guide layer and the transparent electrode, the p-type contact layer being in contact with the transparent electrode on one surface thereof within the opening of the insulating film and in contact with the flat surface of the p-type guide layer on the other surface thereof within the opening of the insulating film, the n-type guide layer is disposed between the n-type clad layer and the active layer, the superlattice layer, in which an InGaN layer and an AlxGa1-xN layer (0≦X<1) are laminated periodically, is in contact with the active layer, the superlattice layer having an average refractive index of 2.6 or lower, the In composition of the InGaN layer is lower than the In composition of the InGaN quantum well layer, and the transparent electrode includes
a first conductive film in ohmic contact with the p-type contact layer, the first conductive film containing an indium oxide-based material, anda second conductive film laminated on the first conductive film and having a thickness greater than a thickness of the first conductive film, the second conductive film containing a zinc oxide-based, gallium oxide-based or tin oxide-based material.