No abstract available

[en] Veterinary antibiotics are frequently used in animal production to treat diseases but also to protect health and to improve growth rate and feed efficiency. Sulfadiazine (SDZ) belongs to the group of sulfonamides which are administered to a great extent in pig production. They are poorly adsorbed in the animal gut so that most on them are excreted unchanged in urine and feces. (Author)

[en] The influence of N content on the crystallization behavior of initially amorphous Ta-Si-N diffusion barriers deposited with a thickness of 10 nm between Cu and SiO₂ was investigated by means of glancing angle X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GD-OES), transmission electron microscopy (TEM), and graphite furnace atomic absorption spectrometry (GF-AAS) after annealing for various times at a temperature of T_an=600 deg. C. For a Ta₇₃Si₂₇ film, only Ta silicide phases (Ta₅Si₃, Ta₂Si) are formed, whereas all barriers containing nitrogen crystallize primarily into a Ta nitride. Si is not incorporated into this phase but diffuses mostly into the Cu film. Although the crystalline Ta nitride grows mainly within the original barrier region, it does not form a continuous layer. For barriers with a N content x_N≥25 at.%, the annealing time necessary to start the crystallization increases and the formed Ta nitride phases become N-richer (Ta₂N→Ta₅N₆). A Ta₃₀Si₁₈N₅₂ layer maintains its amorphous structure even after annealing for t_an=100 h. With increasing N content in the barrier, the thermal stability against Cu diffusion is improved

[en] Typical aero engine alloys, such as IN718, can be surface-treated by shot peening to induce near-surface compressive strains. To calculate the remaining operation time for those critical aero engine components, a quantitative nondestructive determination of near-surface strain gradients has to be developed. We have demonstrated in the past, that it is possible to obtain a characteristic depth profile (surface and sub-surface) of the electrical conductivity of shot peened specimen by using high-frequency eddy current techniques. The measured conductivity profile is resulting from residual stresses, cold work, surface roughness, and the microstructure of the material. The objective is to measure residual stresses (separately from other material properties) in such components after a defined life time. It can be assumed, that surface roughness and microstructure remain unchanged in IN718 materials over their lifetime, but cold work and residual stresses can change independently. Consequently, there is a need to clearly separate the information from both material properties of received eddy current conductivity signals in order to obtain specific information related to residual stresses. This paper presents results acquired from different experiments, conducted to separate both effects by using the eddy current technique on shot peened IN718 materials. We present different physical approaches and illustrate the experiments to solve them. In addition, we will demonstrate that there is a need to use additional techniques, for example ultrasonic time-of-flight measurements, to separate the effects of residual stresses from compound (mixed) signals obtained on cold work samples.

[en] Using glancing angle X-ray diffraction, glow discharge optical emission spectroscopy, and transmission electron microscopy, the crystallization behavior and thermal stability of graded Ta-Si/Ta-Si-N diffusion barriers was analyzed after annealing at various temperatures. For a Ta30Si18N52/Ta73Si27 bilayer and a Ta73Si27/Ta30Si18N52/Ta73Si27 trilayer, nitrogen redistribution within the whole barrier is observed at Tan ≥ 500 deg. C. Further heat supply leads to barrier crystallization into Ta2N. Depositing the layer stacks directly onto silicon, a critical temperature of Cu silicide formation was determined. For graded Ta-Si/Ta-Si-N diffusion barriers, this temperature turned out to be between the corresponding values for Ta73Si27 and Ta30Si18N52 single layers

[en] Reactively sputtered Ta-Si-N _x barrier systems of different nitrogen content on copper were investigated by photoelectron spectroscopy (XPS, UPS) and scanning tunnelling microscopy (STM). The measured photoelectron spectra (excitation He-I) showed a clear dependence of the electron state density near the Fermi edge on the content of nitrogen. These results correlate with the I(U) characteristics of the STM measurements and the electrical conductivity of these layers

[en] Flexible thin-film solar cells require flexible encapsulation to protect the copper-indium-2 selenide (CIS) absorber layer from humidity and aggressive environmental influences. Tantalum-silicon-based diffusion barriers are currently a favorite material to prevent future semiconductor devices from copper diffusion. In this work tantalum-silicon-nitrogen (Ta-Si-N) and tantalum-silicon-oxygen (Ta-Si-O) films were investigated and optimized for thin-film solar cell encapsulation of next-generation flexible solar modules. CIS solar modules were coated with tantalum-based barrier layers. The performance of the thin-film barrier encapsulation was determined by measuring the remaining module efficiency after a 1000 h accelerated aging test. A significantly enhanced stability against humidity diffusion in comparison to non-encapsulated modules was reached with a reactively sputtered thin-film system consisting of 250 nm Ta-Si-O and 15 nm Ta-Si-N

[en] The effect of the nitrogen content on the thermal stability and degradation mechanisms of Ta-Si-N diffusion barriers was studied using methods that prove Cu interdiffusion. On the one hand, glancing angle X-ray diffraction was applied to detect Cu₃Si formation after annealing of Cu/Ta-Si-N/Si layer stacks. On the other hand, a combined secondary ion mass spectroscopy and transmission electron microscopy analysis of Ta-Si-N/Cu/Ta-Si-N/SiO₂/Si samples was performed. For a detailed investigation of the microstructure evolution, the crystallization behavior of both Cu-capped and uncapped Ta-Si-N/Si samples was analyzed using X-ray diffraction. In the case of an uncapped Ta₇₃Si₂₇ film, Si interdiffusion from the substrate precedes the layer crystallization. The substrate influence on the crystallization process decreases with increasing N content x _N of the Ta-Si-N layer. Using Cu/Ta-Si-N/Si samples, a critical temperature for Cu silicide formation was determined. This temperature increases with increasing N content of the Ta-Si-N barrier. In the case of Ta-Si-N films with x _N > 25 at.%, Cu interdiffusion into the substrate occurs before a significant barrier crystallization is observed. For Ta-Si-N layers with x _N ≤ 25 at.%, no indications for Cu diffusion before crystalline phase formation were detected