Process for the preparation of electroluminescent III-V materials containing isoelectronic impurities

Abstract

The disclosure herein pertains to the preparation of semiconductor materials and solid-state devices fabricated therefrom. More particularly, the disclosure pertains to a vapor phase process for the preparation of electroluminescent materials, particularly GaAs 1-x P x , doped with isoelectronic impurities, particularly nitrogen, and to electroluminescent devices fabricated therefrom.

We claim: 
     
       1. A process for the preparation of electroluminescent materials for light-emitting diodes, said process comprising: a. providing in a reaction chamber a substrate of a single-crystal compound formed from Ga and one of the elements selected from the group consisting of As and P;   b. combining in a vapor phase reactant stream reactant material including impurity atoms, said materials being adapted for the formation of GaAs 1-x  P x , wherein x has an initial value within the range of from 0-1 inclusive and a final value within the range of .[.greater than 0.2 to less than 1.0.]. .Iadd.about 0.4 to about 0.9; .Iaddend.   c. introducing said reactant stream into said reactant chamber;   d. epitaxially depositing on said substrate from said stream said reactant materials to form a first epitaxial layer of a first electrical conductivity type on said substrate, said layer constituting a bulk region substantially free of isoelectronic impurities;   e. introducing into said stream an isoelectronic impurity in vapor form;   f. epitaxially depositing on said substrate from said stream said reactant materials to form a second epitaxial layer of said first conductivity type on said first epitaxial layer, said second epitaxial layer providing a surface region containing said isoelectronic impurity atoms; and   g. forming a junction in said surface region by introducing electronic impurity atoms of an electronic conductivity type opposite to that of said first conductivity type.   
     
     
       2. The process according to claim 1 wherein said isoelectronic impurity is nitrogen. 
     
     
       3. The process according to claim 2 wherein the concentration of said reactant materials in said reactant stream is adjusted to provide said first epitaxial layer with a graded composition extending from said substrate to the upper surface of said layer. 
     
     
       4. The process according to claim 2 wherein the concentration of reactant materials in said reactant stream is adjusted to provide said first epitaxial layer with an initial region of graded composition and a final region of constant composition. 
     
     
       5. The process according to claim 2 wherein said P-N junction in step (g) is formed by depositing on said second layer from said stream reactant materials, including isoelectronic impurity atoms, to form an additional layer containing impurity atoms of conductivity type opposite to that previously used. .Iadd. 6. A process for the preparation of electroluminescent materials for light-emitting diodes, said process comprising: a. providing in a reaction chamber a substrate of a single-crystal compound formed from Ga and one of the elements selected from the group consisting of As and P;   b. combining in a vapor phase reactant stream reactant material including impurity atoms, said materials being adapted for the formation of GaAs 1-x  P x , wherein x has an initial value within the range of from 0-1 inclusive and a final value within the range of about 0.4 to about 0.92;   c. introducing said reactant stream into said reactant chamber;   d. epitaxially depositing on said substrate from said stream said reactant materials to form a first epitaxial layer of a first electrical conductivity type on said substrate, said layer constituting a bulk region substantially free of isoelectronic impurities;   e. introducing into said stream an isoelectronic impurity in vapor form;   f. epitaxially depositing on said substrate from said stream said reactant materials to form a second epitaxial layer of said first conductivity type on said first epitaxial layer, said second epitaxial layer providing a surface region containing said isoelectronic impurity atoms; and   g. forming a junction in said surface region by introducing electronic impurity atoms of an electronic conductivity type opposite to that of said first conductivity type. .Iaddend.