Surface emitting semiconductor laser and mehod of fabricating the same

Abstract

A lower mirror is formed on an n-type GaAs substrate. Next, an ion implanted region serving as a current confining region is formed through shallow ion implantation. Then, a SiO 2 film mask is formed, and a multilayer structure including an active region and an upper mirror is selectively grown on an area not covered with the SiO 2 film mask. In this manner, a surface emitting semiconductor laser with a low resistance and a low threshold current is obtained by using ion implantation and selective oxidation through a simplified fabrication process.

What is claimed is:  
     
         1 . A method of fabricating a surface emitting semiconductor laser provided with an active region including an active layer, and a lower mirror and an upper mirror sandwiching said active region, comprising: 
 a first crystal growth step of alternately and repeatedly stacking a first semiconductor layer including Al and a second semiconductor layer matching in lattice size with said first semiconductor layer, whereby forming, on a semiconductor substrate, a first multilayer structure having said second semiconductor layer as an uppermost layer;    a step of forming a mask for defining a closed area on a top surface of said uppermost layer of said first multilayer structure;    an oxidation step of forming a current confining region with a higher electric resistance by selectively oxidizing said first semiconductor layer below said uppermost layer from an area on a top surface of said uppermost layer of said first multilayer structure where said mask is not formed; and    a second crystal growth step of forming a second multilayer structure on said first multilayer structure.    
     
     
         2 . The method of fabricating a surface emitting semiconductor laser of  claim 1 , further comprising a step of forming, on a back surface of said semiconductor substrate, an alignment pattern to be used for specifying a position of said current confining region after said second crystal growth step.  
     
     
         3 . The method of fabricating a surface emitting semiconductor laser of  claim 1 , further comprising, before said second crystal growth step, a step of covering, with a mask, an area on the top surface of said first multilayer structure excluding a selected area, 
 wherein said second multilayer structure is formed on said selected area on the top surface of said first multilayer structure through said second crystal growth step performed by using a selective growth technique.    
     
     
         4 . The method of fabricating a surface emitting semiconductor laser of  claim 1 , 
 wherein said uppermost layer of said first multilayer structure is formed of a GaAs layer.    
     
     
         5 . The method of fabricating a surface emitting semiconductor laser of  claim 4 , 
 wherein said GaAs layer has a thickness of approximately 1 nm through approximately 10 nm.