The impact of light on the copper outplating from aqueous 0.5% HF solutions on 10-20 fl cm (100) silicon wafers is investigated. Illumination is found to drastically increase the copper deposition. A model based on the semiconductor properties of the silicon substrate which describes the copper plating onto silicon is proposed. It is found that the copper deposition onto these silicon surfaces is limited by the minority carrier supply at the wafer surface.

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The in-situ fabrication of rectangular concentration-depth profiles of phosphorus in germanium, with electrically active concentrations approaching 1020 cm-3 is reported. The growth method is atmospheric chemical vapor deposition using germane and phosphine with N2 as carrier gas. Best results have been achieved using a relatively low growth temperature of 350ºC and a low PH3/GeH4 flow ratio, enabling a high concentration of P to be incorporated substitutionally. No P clusters are visible in high-angle annular dark-field STEM images. The results show excellent crystalline quality and acceptable surface uniformity, achieved with growth rates in the range of 5-10 nm / min. There is evidence that further improvements in active concentrations may be achievable by a further reduction in growth temperature and optimization of the gas flow conditions. The process holds promise for future n+junction fabrication in germanium.

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Experiments of depth resolution measurements on silicon with secondary ion mass spectrometry reveal that oxygen primary particles provide always a smaller decay length (better depth resolution) compared with other primary particles for the same penetration depth of the particle. This deviation from the classical collisional mixing model can be explained by a model which does take the incorporation of the primary particle during sputtering into account. For oxygen particles the incorporation is so high that it leads to a different matrix composition at the surface compared with the bulk of the Si sample and it results in a target swelling at the surface. It is now important to realize that the displacements of the atoms are only important relative to the position of the Si atoms in the expanded lattice and that movements with respect to the incorporated oxygen atoms does not matter. The model presented quantifies this effect and gives an accurate estimate of the reduction of the decay lengths. The model predicts a similar behavior for all primary particles with low matrix sputter yield and high incorporation of the primary particle.