IMPROVEMENTS IN OR RELATING TO METHODS OF MANUFACTURING GROUP III-V SEMICONDUCTOR MATERIALS AND TO MATERIALS SO PRODUCED

1,211,358. Nitrogen-doped Group III-V semiconductor. WESTERN ELECTRIC CO. Inc. 7 Nov., 1967 [21 Noy., 1966], No. 50585/67. Heading C1A. [Also in Division H1] Nitrogen-doped Group III-V semi-conductor compounds are produced by preparing Group III-V material under nitrogen-free conditions, preparing a melt of the Group III constituent under nitrogen-free conditions and maintaining it at a constant temperature for 1-2 hours, thereafter adding to the Group III element without the admission of air a minor proportion of the Group III-V material and a required quantity of a nitrogen compound of the Group III constituent, plus any required impurity, sealing the mixture into a container, heating the mixture to its melting point and cooling slowly to effect crystallization. Gallium phosphide is made by passing phosphine over gallium at 850-1100‹ C. and crystallizing the gallium phosphide, maintaining a body of gallium at 1100‹ C. for 1-2 hours, adding the gallium phosphide crystals in a proportion of 1 to 10 by weight and gallium nitride in a required amount plus any required impurity, sealing the mixture into a container, heating to 1200‹ C. and slowly cooling to 850‹ C. to produce nitrogen-doped gallium phosphide. The cooling may take place over 10 hours. The gallium for the initial step may be contained in an alumina boat heated in an alumina-lined furnace. A relationship between the mole per cent of GaN added to Ga and the concentration of N atoms per c.c. of material is shown graphically (Fig. 2, not shown).