| 摘要 |
PURPOSE:To execute an etching process with good accuracy and to reduce the irregular characteristic of a semiconductor laser by forming a semiconductor multilayer film where a second difficult-to-etch semiconductor layer is formed under a first semiconductor layer to be etched by an etching solution capable of etching the layer selectively depending on the composition x of Al and then by etching the multilayer film. CONSTITUTION:After an n-type Al0.5Ga0.5 clad layer 2, an n-type Al0.2Ga0.8As light-confining layer 3, an undoped GaAs active layer 4, a p-type Al0.2Ga0.8As light-confining layer 5, a p-type Al0.5Ga0.5As clad layer 6, a p-type GaAs contact layer 7 have been formed in succession on an n-type (100) GaAs substrate 1, an SiO2 layer 8 is deposited by a plasma CVD method or the like. Then, if the clad layer 6 is etched halfway and is then subjected to a boiling etching process, using HCl, in which the etching rate is changed remarkably around the composition x of Al at 0.4, it is possible to stop the etching operation at the interface between the p-type Al0.5Ga0.5As clad layer 6 and the p-type Al0.2Ga0.8As light-confining layer 5 without piercing the thin p-type Al0.2Ga0.8As light-confining layer with a thickness of 0.5 mum.
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