Semiconductor laser

Abstract

An aluminium gallium indium phosphide (AlGaInP)-based semiconductor laser device is provided. On a main surface of a semiconductor substrate formed of n-type GaAs (gallium arsenide), from the bottom layer, an n-type buffer layer, an n-type cladding layer formed of an AlGaInP-based semiconductor containing silicon (Si) as a dopant, an active layer, a p-type cladding layer formed of an AlGaInP-based semiconductor containing magnesium (Mg) or zinc (Zn) as a dopant, an etching stopper layer, and a p-type contact layer are formed. Here, when an Al composition ratio x of the AlGaInP-based semiconductor is taken as a composition ratio of Al and Ga defined as (Al x Ga 1-x ) 0.5 In 0.5 P, a composition of the n-type cladding layer is expressed as (Al x Ga 1-x ) 0.5 In 0.5 P (0.9<xn<1) and a composition of the p-type cladding layer is expressed as (Al xp Ga 1-xp ) 0.5 In 0.5 P (0.9<xp≦1), and xn and xp satisfy a relationship of xn<xp.

What is claimed is: 
     
         1 . A semiconductor laser device comprising a semiconductor laser,
 wherein the semiconductor laser includes:   an n-type cladding layer having a composition of (Al xn Ga 1-xn ) 0.5 In 0.5 P where 0.9<xn<1;   a p-type cladding layer having a composition of (Al xp Ga 1-xp ) 0.5 In 0.5 P where 0.9<xp≦1;   an active layer provided between the n-type cladding layer and the p-type cladding layer, and   wherein an Al composition ratio xn of the n-type cladding layer and an Al composition ratio xp of the p-type cladding layer satisfy a relationship of xn≦xp.   
     
     
         2 . The semiconductor laser device according to  claim 1 ,
 wherein a difference between the Al composition ratio xp of the p-type cladding layer and the Al composition ratio xn of the n-type cladding layer satisfies a relationship of 0≦xp−xn≦0.08.