Surface-emitting laser and image forming apparatus using the same
AssigneeCanon Kabushiki Kaisha
InventorsYasuhisa Inao, Mitsuhiro Ikuta, Tetsuya Takeuchi
Life of this patent
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Abstract
A surface-emitting laser that can prevent delamination at the interface of a selective oxidation layer and a spacer layer, while suppressing any rise of voltage, to improve the reliability of operation.
Claims11
A surface-emitting laser comprising:
- an n-type semiconductor Bragg reflector arranged on a substrate;
- an active layer including Al, Ga, In and P formed on said n-type semiconductor Bragg reflector;
- a p-type spacer layer including Al, In and P and formed on said active layer;
- a selective oxidation layer including AlzGa1−zAs and formed on said p-type spacer layer;
- a p-type semiconductor Bragg reflector including Al, Ga and As and formed on said selective oxidation layer;
- a first intermediate layer including AlxGa1−xAs and arranged between said selective oxidation layer and said p-type spacer layer so as to adjoin said selective oxidation layer;
- a second intermediate layer including AlyGa1−yAs and arranged between said selective oxidation layer and said p-type spacer layer so as to adjoin said first intermediate layer;
- and
- a third intermediate layer including Al, Ga, In and P and arranged between said selective oxidation layer and said p-type spacer layer so as to adjoin said second intermediate layer,
- wherein z, y, x satisfy the relationship z>y>x, and
- wherein a top of the valence band of said third intermediate layer is closer to a top of the valence band of said second intermediate layer than to a value halfway between the top of the valence band of said second intermediate layer and a top of the valence band of said p-type spacer layer.
A surface-emitting laser comprising an n-type semiconductor Bragg reflector, a p-type semiconductor Bragg reflector, and an active layer arranged between the reflectors, the reflectors and the active layer being laminated on a substrate, the p-type semiconductor Bragg reflector being arranged on the active layer through a p-type spacer layer and a selective oxidation layer, a current confinement structure being formed by oxidizing the selective oxidation layer, comprising:
- a first intermediate layer arranged so as to adjoin the selective oxidation layer and included a material free from progress of oxidation when oxidizing the selective oxidation layer;
- a second intermediate layer arranged so as to adjoin the first intermediate layer to adjust a difference between band gap values of the p-type spacer layer and the first intermediate layer;
- and
- a third intermediate layer arranged so as to adjoin the second intermediate layer to adjust a difference between band gap values of the p-type spacer layer and the first intermediate layer,
- wherein the first intermediate layer, the second intermediate layer, and the third intermediate layer are arranged between the selective oxidation layer and the p-type spacer layer.
Dependencies are inferred from the claim text.