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[en] An extensive study of lattice parameters of silicon doped gallium arsenide grown by liqiud-phase epitaxy, vapour-phase epitaxy and gradient-freeze techniques has been undertaken. Lattice parameters were measured by the Bond techniques to a precision of 1 ppm, and the material studied was also characterised independently for carrier concentration, carrier mobility, and in some cases, for silicon site distribution by infra-red LVM measurements. It is concluded that the p-type LPE layers show a very large lattice contraction compared with undoped material, while VPE and gradient-freeze material have parameters much closer to the undoped value. The lattice contraction in Si-doped LPE layers is about 6 x 10^-4 A at hole concentration levels of 6 x 10¹⁸ cm^-3, and the contraction is roughly proportional to the free-hole concentration from 1 to 6 x 10¹⁸ cm^-3. It is concluded that the p-type Si-doped LPE layers studied contain a high concentration of a contracting defect associated with silicon whose concentration is related to the free-hole concentration. The most likely defect responsible is Sisub(G)sub(a), present in high concentrations as a compensating donor, although other defects cannot be ruled out. (orig.)

[en] Investigation of the interactions between sequential gallium-phosphorus and gallium-arsenic diffusions have been made using radiotracer profiling techniques. Gallium diffusions were first carried out using isotope ⁶⁷Ga diffused from a solid gallium oxide source, and subsequently phosphorus or arsenic were diffused into the same surface. The effect of phosphorus diffusion of high surface concentration was found to be a large enhancement (up to a factor of 100)in the diffusion coefficient of the tail of the gallium profile, while similar arsenic diffusion produced either a small enhancement or a retardation, depending on the conditions used. In addition, the diffusion of both phosphorus and arsenic produced a pronounced dip in the gallium profiles, which is discussed in terms of the built-in electric field produced during the emitter diffusions. The differences between the positions of the dips produced by phosphorus and arsenic are explained by the differences in their profile shape and hence in the electric field distribution. In the case of arsenic, the dip is located at the steeply falling front of the arsenic profile which resolves discrepancies in previous studies of boron-arsenic sequential diffusions. (author)

[en] Results of arsenic diffusion under intrinsic diffusion conditions in Si and SiGe (5, 10% Ge) alloys are presented. Epitaxial Si and compressively strained SiGe structures with buried marker layers of arsenic were grown using Molecular Beam Epitaxy. The concentration profiles before and after Rapid Thermal Annealing at 1000 deg. C have been measured using SIMS. An enhancement of intrinsic arsenic diffusivity in SiGe compared to Si is observed, in agreement with literature. However, for As in Si_0.95Ge_0.05 strain seems to compensate the effect of enhancement due to Ge chemical effect although for Si_0.9Ge_0.1 the chemical effect overcomes the retardation due to strain