Optical semiconductor device and method for fabricating the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsJun Shimizu, Tetsuzo Ueda, Toshikazu Onishi
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Abstract
An optical semiconductor device includes an active layer having a quantum well structure including alternately stacked well layers and barrier layers with a larger band gap than the well layers. The band gap of each of the well layers and the barrier layers is constant, each well layer is uniformly provided with compression strain and each barrier layer is provided with large extension strain in a center portion thereof along the thickness direction and small extension strain in portions thereof in the vicinity of the well layers.
Claims18
An optical semiconductor device comprising:
- an active layer having a quantum well structure including alternately stacked well layers and barrier layers with a larger band gap than said well layers,
- wherein each of said well layers and said barrier layers has a constant band gap, and
- each of said well layers is uniformly provided with compression strain and each of said barrier layers is provided with large extension strain in a center portion thereof along a thickness direction and small extension strain in portions thereof in the vicinity of said well layers.
A method for fabricating an optical semiconductor device made of a group III-V compound semiconductor, comprising the steps of:
- (a) forming a well layer over a substrate;
- (b) forming a barrier layer with a larger band gap than said well layer on said well layer;
- and
- (c) forming an active layer with a quantum well structure including said well layer and said barrier layer alternately stacked by repeating the step (a) and the step (b) a plurality of times,
- wherein said well layer is uniformly provided with compression strain and said barrier layer is provided with large extension strain in a center portion thereof along a thickness direction and small extension strain in a portion thereof in the vicinity of said well layer by forming said well layer with composition ratios of group III elements and group V elements being constant in the step (a) and by forming said barrier layer with composition ratios of group III elements and group V elements being varied along a thickness direction in the step (b).
Dependencies are inferred from the claim text.