| 摘要 |
PROBLEM TO BE SOLVED: To obtain an element structure which can yield excellent crystals even when well layers having large strain quantities are used by laminating the well layers having compressive strains of a specific value or larger against the lattice constant of a substrate and barrier layers having strain values of a specific value or smaller and a specific film thickness or thicker upon another. SOLUTION: The figure shown a typical figure of the basic structure of a strained multiple quantum well structure. Namely, a multiple strained quantum well structure composed an n-type InP buffer layer 11, a strained multiple quantum well structure composed of an InGaAsP guide layer 12 making lattice matching to an n-type InP substrate 10, an InGaAs well layer 14, and an InGaAs barrier layer 13, an InGaAsP guide layer 15 making lattice matching to the substrate 10, and an InP cap layer 16 are formed on the substrate 10. In this strained multiple quantum well structure using the InGaAs layer 14 having a compressive strain of >=+1.2%, the strain quantity and film thickness of the barrier layer 13 are respectively adjusted to <=±0.2% and >=15nm. |
