Semiconductor light emitting device and fabrication method for semiconductor light emitting device
A semiconductor light emitting device includes a lower cladding layer, an active layer, and an AlGaAs upper cladding layer mounted on a GaAs substrate. The semiconductor light emitting device has a ridge structure including the AlGaAs upper cladding layer. The semiconductor light emitting device further includes an InGaAs etching stop layer provided in contact with the lower side of the AlGaAs upper cladding layer. The InGaAs etching stop layer has a band gap greater than that of the active layer.
1. A semiconductor light emitting device, comprising:
a lower cladding layer, an active layer, an InGaAs etching stop layer, and an AlGaAs upper cladding layer provided over a GaAs substrate;
said InGaAs etching stop layer being provided in contact with the lower side of said AlGaAs upper cladding layer and being provided in contact with the upper side of a GaAs layer or an AlGaAs layer;
said semiconductor light emitting device having a ridge structure including said AlGaAs upper cladding layer and said InGaAs etching stop layer;
the upper side of said GaAs layer or said AlGaAs layer being exposed on opposite sides of said ridge structure;
said InGaAs etching stop layer having a band gap greater than that of said active layer; and
the Al composition ratio of said AlGaAs upper cladding layer being 0.4 or less.
2. The semiconductor light emitting device as claimed in claim 1 , wherein said GaAs layer or said AlGaAs layer is a different AlGaAs upper cladding layer provided in contact with the upper side of said active layer.
3. The semiconductor light emitting device as claimed in claim 1 , wherein said GaAs layer or said AlGaAs layer is an uppermost GaAs layer included in said active layer.
4. The semiconductor light emitting device as claimed in claim 1 , wherein said GaAs substrate is a p-type conductive substrate, an n-type conductive substrate or a high-resistance substrate.
5. The semiconductor light emitting device as claimed in claim 1 , wherein said active layer is a quantum well active layer, a quantum wire active layer or a quantum dot active layer.
6. The semiconductor light emitting device as claimed in claim 1 , wherein said active layer is formed from one of semiconductor materials of the group consisting of GaInNAs, InAs, InGaAs and InGaAsSb.
7. The semiconductor light emitting device as claimed in claim 1 , further comprising:
a contact layer located at a top portion of the ridge structure; and
an electrode being only in contact with the contact layer.
8. The semiconductor light emitting device as claimed in claim 1 , wherein a top face of the ridge structure is perpendicular to a side face of the ridge structure.