P-N JUNCTION LASER DEVICES

摘要

1282443 Semi-conductor lasers TEXAS INSTRUMENTS Inc 20 Aug 1969 [30 Dec 1968] 41530/69 Headings H1C and H1K [Also in Division C4] A semi-conductor laser, Fig. 4, comprises a cleaved body of N-type material, e.g. gallium arsenide, in which an acceptor dopant, e.g. zinc, is diffused to form parallel strip regions 16, 17, 18 of P-type material with the inner region 16 of lesser depth than the outer regions 17, 18, the inner region 16 forming a P-N junction, while the outer regions 17, 18 provide radiation intercepting regions for absorbing radiation emitted from the junction transverse to the emission output axis. The P-type regions are formed by the sequential deposition and selective etching of masking layers 12, 13, 14 and 15, Fig. 2, followed by diffusion at a temperature of about 925‹ C. in a ZnAs 2 + Ga 2 S 3 atmosphere. The masking layers 12, 13 are of phosphorusdoped silicon dioxide impervious to zinc, while the masking layers 14, 15 are both of silicon dioxide, the layer 15 being individual to the regions 17, 18 and therefore permitting deeper penetration of the zino dopant than at region 16 where the layers 14, 15 are superimposed. All the layers may be removed when diffusion is completed and replaced by a single layer of SiO 2 , a window for an electrode being provided. Both electrodes may consist of nickel-plated gold antimony alloy. Other semi-conductor materials disclosed are gallium antimonide, indium phosphide, indium arsenide, indium antimonide and mixed crystals, while suitable dopants are tin, tellurium, sulphur, germanium, silicon, cadmium and magnesium. Dopant concentration is in the range of about 5Î 1017 to 5 Î 1018 donor atoms per c.c. An alternative diffusion process involves the use of zinc alone and redistribution of the diffused zinc atoms by post-diffusion heat treatment.