Abstract: In this work we present for the first time, to our knowledge, the CVD epitaxial growth of beta -SiC using an ion beam synthesized (IBS) beta -SiC layer as seed, which has been formed by multiple implantation into Si wafers at 500 degreesC. The ion beam synthesized continuous layer is constituted by beta -SiC nanocrystals that are well oriented relative to the silicon substrate. Comparison of the epitaxial growth on these samples with that on silicon test samples, both on and off-axis, is performed. The results show that the epitaxial growth can be achieved on the IBS samples without the need of the carbonization step and that the structural quality of the CVD layer is comparable to that obtained on a carbonized silicon sample. Improvement of the quality of the deposited layer is proposed.

Abstract: In situ irradiation experiments in a high resolution electron microscope JEOL-4000EX at room temperature resulted in discovery of the isolated and combined clustering of vacancies and self-interstitial atoms on {111}- and {113}-habit planes both leading to an extended defect formation in Si crystals. The type of the defect is strongly affected by the type of supersaturation of point defects depending on the crystal thickness during electron irradiation. Because of the existence of energy barriers against recombination of interstitials with the extended aggregates of vacancies, a large family of intermediate defect configurations (IDCs) is formed on {113}- and {111}-habit planes at a low temperature under interstitial supersaturation in addition to the well-known {133}-defects of interstitial type. The formation of metastable IDCs inside vacancy aggregates prevents a way of recombination of defects in extended shape.

Abstract: We present a detailed analysis of the point-defect clustering in strained Si/Si(1-x)Ge(x)/(001)Si structures, including the interaction of the point defects with the strained interfaces and the sample surface during 400 kV electron irradiation at room temperature. Point-defect cluster formation is very sensitive to the type and magnitude of the strain in the Si and Si(1-x)Ge(x) layers. A small compressive strain (-0.3%) in the SiGe alloy causes an aggregation of vacancies in the form of metastable [110]-oriented chains. They are located on {113} planes and further recombine with interstitials. Tensile strain in the Si layer causes an aggregation of interstitial atoms in the forms of additional [110] rows which are inserted on {113} planes with [001]-split configurations. The chainlike configurations are characterized by a large outward lattice relaxation for interstitial rows (0.13 +/-0.01 nm) and a very small inward relaxation for vacancy chains (0.02+/-0.01 nm). A compressive strain higher than -0.5% strongly decreases point-defect generation inside the strained SiGe alloy due to the large positive value of the formation volume of a Frenkel pair. This leads to the suppression of point-defect clustering in a strained SiGe alloy so that SiGe relaxes via a diffusion of vacancies from the Si layer, giving rise to an intermixing at the Si/SiGe interface. In material with a 0.9% misfit a strongly increased flow of vacancies from the Si layer to the SiGe layer and an increased biaxial strain in SiGe bath promote the preferential aggregation of vacancies in the (001) plane, which relaxes to form intrinsic 60 degrees dislocation loops.

Abstract: The formation of Ni silicides is studied by transmission electron microscopy during in situ heating experiments of 12 nm Ni layers on blanket silicon, or in patterned structures covered with a thin chemical oxide. It is shown that the first phase formed is the NiSi2 which grows epitaxially in pyramidal crystals. The formation of NiSi occurs quite abruptly around 400 degreesC when a monosilicide layer covers the disilicide grains and the silicon in between. The NiSi phase remains stable up to 800 degreesC, at which temperature the layer finally fully transforms to NiSi2. The monosilicide grains show different epitaxial relationships with the Si substrate. Ni2Si is never observed. (C) 2001 American Institute of Physics.

Abstract: The reaction of a Ti (8 nm) capped Co film (15 nm) with a Si3N4 layer (150 nm) is studied after rapid thermal annealing at 660 degreesC for 120 s in a N-2 ambient. X-ray photoelectron spectroscopy, transmission electron microscopy, electron energy-loss spectroscopy, and Auger electron spectroscopy are used to study the reaction products. Combining the results of the different analyses yields a layer stack consisting of: TiO2/TiO/unreacted Co/(Ti,Co)(2)N/Co2Si, followed by amorphous Si3N4. The reaction mechanisms are discussed. Conclusions concerning the risk for degradation of nitride spacers in advanced devices are drawn. (C) 2000 American Institute of Physics. [S0003-6951(00)05248-7].