Patent ID: 7586967

Claim:
A semiconductor layer having a double hetero mesa-stripe serving as a first semiconductor laminated product including at least a quantum well active layer formed by selective growth on a semiconductor substrate, and recombined layers serving as second semiconductor laminated products simultaneously formed on both the sides of the double hetero mesa-stripe at a predetermined interval in the selective growth, wherein when an average strain amount ε(average) and a critical strain amount ε(critical) are defined by the following equations: ɛ ⁡ ( average ) = ∑ i = 1 n ⁢ ( ɛ ⁢ ⁢ i ⨯ di ) d ⁢ ⁢ d = ∑ i = 1 n ⁢ di [ Equation ⁢ ⁢ 1 ] where the number of strained semiconductor layers is represented by j, the number of unstrained semiconductor layers sandwiched by the strained semiconductor layers is represented by k, and a strain amount of an i-th semiconductor layer and a thickness of the i-th semiconductor layer in the double hetero mesa-stripe or the recombination layers obtained by laminating n (n=j+k) semiconductor layers are represented by εi and di, respectively, ɛ ⁡ ( critical ) = b 4 ⁢ ⁢ π ⁢ ⁢ d ⁡ ( critical ) · 1 - p · ( cos ⁢ ⁢ α ) ^ 2 ) ( 1 + p ) · cos ⁢ ⁢ λ · { ln ⁡ ( d ⁡ ( critical ) b ) + 1 } { Equation ⁢ ⁢ 2 ] where b: Strength of Burgers vector, p: Poisson's ratio α: angle between a dislocation line and its Burgers vector λ: angle between a slip direction and a direction perpendicular to cross lines of a slip surface and a laminate surface and being in the laminate surface, an average strain amount ε1(average) of the double hetero mesa-stripe is a compression strain (ε1(critical)≧ε1(average)>0, and an average strain amount ε2(average) of the recombination layer is a tensile strain (−ε2(critical)≦ε2(average)<0) not more than a critical strain amount ε2 (critical) or zero strain (ε2(average)=0).