Current confinement in semiconductor lasers

Claim 1

In a double heterostructure semiconductor junction laser, a structure comprising: a semiconductor body including a pair of opposite conductivity type AlGaAs cladding layers; and a narrower bandgap Al z Ga 1-z As (0 ≦ z ≲ 0.4) active region bounded by said layers; an electrical contact to a p-type major surface of said body for applying forward-bias pumping current to said active region; a low resistivity, stripe-like channel through which said current flows from said contact to said active region, thereby to cause recombination of holes and electrons and the emission of stimulated radiation from said active region; a pair of laterally spaced, higher resistivity proton bombarded zones which bound said channel and constrain said current to flow through said channel characterized in that a Zn diffused semiconductor zone, wider than said channel, separates said contact from said higher resistivity zones and has a lower resistivity than said latter zones so that current from said contact spreads into a semiconductor area wider than said channel before entering said channel and further characterized in that said structure is fabricated by a process which includes the steps of epitaxially growing said active region and cladding layers, selectively proton bombarding the uppermost epitaxial surface down to a depth of approximately said active region to form said higher resistivity proton bombarded zones, and then diffusing Zn atoms into said surface to form said Zn diffused semiconductor zone.