Fabrication of junction laser devices having mode-suppressing regions

Claim 1

A method as defined by claim 1 wherein said semiconductor crystal is selected from the group consisting of gallium arsenide, gallium antimonide, indium phosphide, indium arsenide, indium antimonide, and mixed crystals including any two of said compounds.

Claim 3

A method for the fabrication of a p-n junction device comprising: a. depositing a first diffusion masking layer, substantially impermeable to a selected conductivity type producing impurity, on a surface of a direct band gap semiconductor crystal of opposite conductivity type; b. selectively removing a portion of said first masking layer to leave on said crystal a substantially parallel pair of masking strips; c. depositing a second diffusion masking layer on said crystal surface and on said strips; d. selectively removing a portion of said second masking layer to leave on said crystal a layer covering said elongated strips and covering at least a portion of the area of said crystal surface lying between said strips; e. depositing a third diffusion masking layer on said crystal surface covering said second masking layer and covering at least a portion of the remainder of said crystal surface; and f. exposing said crystal to said selected impurity, at diffusion conditions, whereby selective diffusion of said impurity into said crystal occurs through said second and third masking layers, but not through said first masking layer, and at a relatively greater rate into the regions of said crystal covered by said third masking layer only than into the region covered by both said second and third masking layers, thereby forming a relatively shallow p-n junction spaced between two relatively deeper p-n junctions.