the inp cover layer 11 on the other hand no solution by which only indium particles on the ingaasp contact layer can be melted or removed has been found thus the inp cover layer for which there is a suitable etchant is needed to remove indium particles then as shown in fig4 c the inp cover layer 11 on the ingaasp contact layer 7 can be selectively removed by an etching process using hcl or hbr as an etchant so that the previously formed contact layer 7 is exposed the inventor found by using an optical microscope that no indium particles were seen on the ingaasp contact layer 7 as explained above since a solution by which indium on ingaasp can be selectively removed has not been found a combination of ingaasp inp in particles is used in the present invention first indium particles are selectively removed by a mixed solution of hf and hno 3 second inp is selectively removed by hcl or hbr with the result that indium particles left on the ingaasp can be removed thus an improved ld according to the present invention is produced fig5 is a graph of the lifetime of light emitting devices of the prior art and the present invention when the indium particles.