Semiconductor laser device and method for fabricating the same and strained quantum well crystal and method for fabricating the same

DETAILED DESCRIPTION The semiconductor laser device of the invention includes: a strained quantum well structure including a well layer and a barrier layer, and a semiconductor substrate for supporting the strained quantum well structure.
In the semiconductor laser device, at least one of the well layer and the barrier layer is composed of a mixed crystal where an atomic ordering is generated.
In one embodiment, the semiconductor laser device further includes a first optical waveguide layer and a second optical waveguide layer so as to sandwich the strained quantum well structure therebetween.
In another embodiment, the semiconductor substrate is composed of InP, and the well layer and the barrier layer are composed of an InGaAsP crystal having respectively different energy band gaps.
According to another aspect of the present invention, a method for fabricating a semiconductor laser device including a strained quantum well structure including a well layer and a barrier layer is provided.
In this method, a process for forming the strained quantum well structure includes a process step for forming at least one of the well layer and the barrier layer by using a mixed crystal where an atomic ordering is generated.
In one embodiment, the process step for forming the well layer includes the steps of: introducing a lattice strain in an amount expressed by an equation: strain amount (%)=1.
0-0.
10.
times.
(a number of the well layers), or more; and growing the well layer at a temperature of 580.
degree.
C.
or lower.
In another embodiment, the process step for forming the well layer includes the steps of: introducing a lattice strain in an amount expressed by an equation: strain amount (%)=1.
2-0.
02.
times.
(a number of the well layers), or more; and growing the well layer at a temperature of 600.
degree.
C.
or lower.
In still another embodiment, the process step for forming the well layer includes the steps of: introducing a lattice strain in an amount expressed by an equation: strain amount (%)=1.
6-0.
02