US Patent 7652281 Light emitting diode

On a GaAs substrate 1, a light emitting part 4, an intermediate layer 5 of AlGaInP and a current spreading layer 6 are sequentially formed. The light emitting part 4 includes a first conductivity type AlGaInP based lower cladding layer 41, an AlGaInP based light emitting layer 42, and a second conductivity type AlGaInP based upper cladding layer 43 sequentially formed on the GaAs substrate 1. In each layer of the light emitting part 4, a hydrogen concentration is not more than 2×1017 cm−3, a carbon concentration is not more than 2×1016 cm−3, and an oxygen concentration is not more than 2×1016 cm−3. In a partial region or in a total region of the current-spreading layer 6, a hydrogen concentration is not more than 5×1017 cm−3, a carbon concentration is not more than 5×1017 cm−3, and an oxygen concentration is not more than 2×1016 cm−3.