Defect and Diffusion Forum Vol. 264

Abstract: The stress state and intermixing in epitaxial Ni/Mo multilayers grown on (11 2 0) sapphire substrates are investigated using X-ray Diffraction (XRD). Two deposition techniques were used, namely ion beam sputtering (IBS) and magnetron sputtering (MS), to vary the energy of the deposited species. In both cases, high-quality superlattices with a Nishiyama-Wasserman epitaxial relationship Ni [110] (111) // Mo [001] (110) were obtained. The residual stress state appears rather complex, resulting from two contributions: a growth-stress whose magnitude and sign depend on growth conditions and coherency stresses of opposite signs in the two elemental sublayers (tensile for Ni and compressive for Mo). Post-growth ion irradiation at low fluences was used to induce structural changes in a controlled way. For the case of IBS, it resulted in partial stress relaxation, as the growth stress could be almost fully relaxed, while the coherency stresses remained unchanged. For the case of MS, a distinct behavior was found: a stress increase of the tensile component of Mo-sublayers was observed, while a stress reduction of the compressive component was noticed. We attribute this phenomenon to ion irradiation induced intermixing. For the Ni sublayers, this intermixing leads to a stress relaxation. The modeling of the stress evolution during ion irradiation was performed using a triaxial stress analysis which enabled us to determine the ‘stress-free and defect-free lattice parameter’, solely linked to chemical effect.

Abstract: Redistributions of implanted species after thermal annealing in polycrystalline silicon (poly-silicon) were studied by secondary ion mass spectrometry. Ten different elements were implanted into poly-silicon films grown on Si substrates. The implanted energies were chosen such that the expected ion range is within the poly-silicon film. Thermal anneals were carried out at temperatures between 300°C and 1000°C in flowing high purity Ar gas. Three different diffusion behaviors have been observed for these elements. For Be, Na, Ga, and Cr, most of the implanted ions diffused out to the surface of the poly-silicon film after anneal at 1000°C. For K, Ca, Ti, and Ge, the impurity ions diffused deeper into the bulk after anneal at 1000°C. For Cl and Mn ions, the concentration distributions became narrower when annealed at high temperatures.

Abstract: In order to investigate interdiffusion in Mo/V multilayers, we present a method that combines both kinetic mean-field simulations and calculations of x-ray scattered intensity with disorder effects. Considering preliminary experimental data obtained on Mo(4nm)/V(2nm) multilayers, we show that the angular shift of spectra observed after annealing, should take place for both Fickian and asymmetric interdiffusion modes. In contrast, clear signatures of the interdiffusion modes are found from the simulation of the peak intensities. These results offer interesting perspectives for a full analysis of the interdiffusion in these systems.

Abstract: We have investigated the redistribution of B during the crystallization of an amorphous Si layer homogeneously doped with P. The redistribution of B only occurs for concentrations lower than 2 × 1020 at cm−3. Crystallization leads to a non “Fickian” redistribution, allowing an abrupt interface between the regions doped and undoped with B. Once the crystallization is ended, B diffuses through the layer in the type B regime with a coefficient which is in agreement with the literature data for diffusion in polycrystalline Si. Although the P distribution is homogeneous in the entire layer, for a temperature as high as 755 °C, P diffuses towards the region the most concentrated in B. The B and P interactions are interpreted as chemical interactions.

Abstract: Grain boundary and free surface tension for pure copper and copper-tin alloys are measured. On the base of these data isothermes of grain boundary tension, free surface tension and isothermes of adsorption are constructed in assumption of a dilute solution. Grain boundary diffusion coefficients of copper were calculated by using the relation of Borisov et. al. for copper and copper-tin alloys.