A plane emission type semiconductor laser device includes, on an n-type GaAs
stepped
substrate, a laminate structure of a lower reflector, a lower clad layer, an active
layer, an upper clad layer, an upper reflector, and a p-type contact layer. The
stepped substrate includes a circular (100) plane upper level portion, a step portion,
and an annular (100) plane lower level portion surrounding the upper level portion
with the step portion therebetween. When an AlAs layer is grown as a current confinement
layer on the stepped substrate while implanting Si as an n-type impurity into the
AlAs layer being grown, the impurity concentration in the AlAs layer on the upper
side of the upper level portion is higher than that on the upper side of the step
portion, and the oxidation rate of the AlAs layer on the upper side of the upper
level portion is lower than that on the upper side of the step portion, so that
the progress of oxidation of the AlAs layer on the upper side of the upper level
portion is autonomously restrained. By time control of the oxidation reaction of
the AlAs layer, it is possible to maintain the circular AlAs layer on the upper
side of the upper level portion in an unoxidized state with an accurate shape and
an accurate area.