Patent ID: 8258529
Filing Date: 2012-09-04
Classification: H01L

Abstract:
1. A light-emitting element, comprising: a semiconductor substrate; a light emitting portion comprising an active layer sandwiched between a first cladding layer of a first conductivity type and a second cladding layer of a second conductivity type different from the first conductivity type; a reflective portion provided between the semiconductor substrate and the light emitting portion for reflecting light emitted from the active layer; and a current spreading layer provided on the light emitting portion opposite to the reflective portion and comprising a concavo-convex portion on a surface thereof, wherein the reflective portion comprises a plurality of pair layers each comprising a first semiconductor layer and a second semiconductor layer different from the first semiconductor layer, and the first semiconductor layer has a thickness T wherein T A1 ≧λ p /4n A , T B1 ≧λ p /4n B , is a peak wavelength of the light emitted from the active layer, n A is a refractive index of the first semiconductor layer, n B is a refractive index of the second semiconductor layer, n In is a refractive index of the first cladding layer, and θ is an incident angle which is defined as an angle with respect to a normal line of an incident plane from the first cladding layer to the first semiconductor layer, wherein the reflective portion comprises at least three pair layers, thicknesses of a plurality of the pair layers are different from each other due to a θ value in the formulas (1) and (2) being different in each of a plurality of the pair layers, and at least one of a plurality of the pair layers comprises the first and second semiconductor layers with a θ value of not less than 50°.