Epitaxial wafer for semiconductor light emitting diode and semiconductor light emitting diode using same
An epitaxial wafer for a semiconductor light emitting device according to the present invention in which at least an n-type cladding layer formed with a mixed crystal made of an AlGaInP material, an active layer, a p-type Mg-doped cladding layer, and a p-type contact layer are stacked successively in that order on an n-type GaAs substrate, and the p-type contact layer is formed as at least two layers that are an Mg-doped contact layer and a Zn-doped contact layer stacked thereon when viewed from the n-type GaAs substrate, comprises a Zn-doped layer which is inserted between the p-type Mg-doped cladding layer and the p-type contact layer.
1. An epitaxial wafer for a semiconductor light emitting device, comprising an n-type GaAs substrate and a plurality of layers stacked on the n-type GaAs substrate, the plurality of layers including at least:
an n-type cladding layer formed with a mixed crystal made of an AlGaInP material; an active layer containing a multiple quantum well structure; a p-type Mg-doped cladding layer; a p-type Mg-doped intermediate layer; and a p-type contact layer, which are stacked successively in that order on the n-type GaAs substrate,
wherein the p-type contact layer comprises a p-type Mg-doped contact layer and a p-type Zn-doped contact layer, the p-type Mg-doped contact layer is between the p-type Mg-doped cladding layer and the p-type Zn-doped contact layer; and
further including a Zn-doped layer between the p-type Mg-doped cladding layer and the p-type Mg-doped intermediate layer, the Zn-doped layer adjusting Zn diffusion into the p-type Mg-doped cladding layer,
wherein Zn concentration of the Zn-doped layer is within a range from 1.0×10 19 to 2.5×10 19 cm −3 .
2. The epitaxial wafer for a semiconductor light emitting device according to claim 1 , wherein:
the p-type Mg-doped intermediate layer is replaced by a p-type Zn-doped intermediate layer.
3. The epitaxial wafer for a semiconductor light emitting device according to claim 2 , wherein:
the p-type Zn-doped intermediate layer is a p-type Zn-doped GaInP layer.
4. The epitaxial wafer for a semiconductor light emitting device according to claim 1 , wherein:
the Zn-doped layer is a Zn-doped GaAs layer.
5. The epitaxial wafer for a semiconductor light emitting device according to claim 1 , wherein:
the Zn-doped layer is a Zn planer-doped layer.
6. A semiconductor light emitting device formed by using the epitaxial wafer for a semiconductor light emitting device according to claim 1 .
7. The epitaxial wafer for a semiconductor light emitting device according to claim 1 , wherein:
a thickness of the Zn-doped layer is 50 nm or less.
8. The epitaxial wafer for a semiconductor light emitting device according to claim 1 , wherein:
average Zn concentration in the p-type Mg-doped cladding layer is more than 1×10 15 cm −3 and 1.3×10 18 cm −3 or less.
9. The epitaxial wafer for a semiconductor light emitting device according to claim 1 , wherein:
the p-type Mg-doped intermediate layer is a p-type Mg-doped GalnP layer.