Double heterostructure stripe geometry semiconductor laser device

Abstract

A semiconductor laser device includes a narrow elongated semiconductor region of the same conductivity type as another semiconductor region lying in the vicinity of the active region of the laser device. The elongated region extends in depth from the surface of the device to the vicinity of the active region. A surface semiconductor layer of an opposite conductivity type covers the entire surface of the device except for the elongated region.

I claim: 
     
       1. A GaAs-Al x  Ga 1-x  As double heterostructure injection laser comprising an N-type GaAs substrate, a first layer made of N-type Al x  Ga 1-x  As epitaxially grown on one major surface of said substrate, a second layer made of GaAs epitaxially grown on said first layer, a third layer made of P-type Al 2  Ga 1-x  As epitaxially grown on said second layer, a fourth layer made of N-type GaAs epitaxially grown on said third layer, a silicon dioxide film formed on said fourth layer and having a stripe-shaped opening formed therein, and a thin elongated P-type region formed on the surface of said .[.forth.]. .Iadd.fourth .Iaddend.layer through the selective diffusion of P-type impurities through said stripe-shaped opening and into said fourth layer and extending past the junction between said third and fourth layers and into a portion of said third layer, a first electrode covering said silicon dioxide film and said .[.elongaged.]. .Iadd.elongated .Iaddend.region, and a second electrode in ohmic contact with the other major surface of said substrate; wherein excitation current supplied through said first electrode is allowed to flow substantially only through the deepest portion of said thin elongated p-type region as the result of a reverse bias developed between said third and fourth layers.