Patent ID: 7736922

Claim:
A method of fabricating an AlGaAs-based ridge-stripe semiconductor laser element comprising the steps of: forming a stacked structure on an active layer section, said stacked structure comprising an Al x Ga 1−x As (0<x<1) first cladding layer, an Al z Ga 1−z As (0<z≦1) etching stop layer, an Al x Ga 1−x As (0<x<1) second cladding layer, an Al y Ga 1−y As (0<y<1) third cladding layer, and a GaAs contact layer, said etching stop layer being in contact with said first cladding layer and said second cladding layer, and having Al compositional ratio “z” of said etching stop layer, Al compositional ratio “x” of said first cladding layer and said second cladding layer, and Al compositional ratio “y” of said third cladding layer satisfying the relations x<z and x<y, where a difference between “x” and “z” is set to 0.025 or more; and forming a stripe-patterned ridge by wet-etching said contact layer, said third cladding layer and said second cladding layer, wherein, said ridge forming step further comprises: a first etching step of wet-etching part of said contact layer, said third cladding layer, and said second cladding layer; and a second etching step of etching the residual portion of said second cladding layer up to said etching stop layer, by using an etchant comprising a mixed solution of an aqueous citric acid solution and an aqueous hydrogen peroxide solution.