A TEM specimen holder has been developed for the measurement of the electrical resistance of a TEM sample as a function of temperature. A Philips TEM heating holder was modified for this purpose. This creates the opportunity to directly correlate changes in the resistance to microstructural changes as a function of temperature.

The microstructure of Al-Ge films of several thicknesses has been studied in an in-situ annealing experiment and has been recorded on videotape, while simultaneously acquiring resistance data. These in-situ TEM studies confirm that the irreversible decrease in resistance of these films is caused by crystallisation. During this transition segregation occurs, resulting in crystalline Al and Ge phases.

Well-annealed thin films are typically observed to exhibit mean grain diameters that are approximately equal to the film thickness. The standard explanation of this “sheet thickness effect” is that it results from a balance of grain boundary curvature in two different directions which, in turn, results from pinning at grain boundary grooves. TEM experiments have been performed to assess this model, and it is found that the predicted curvature about axes in the film plane is absent. Alternate explanations of the sheet thickness effect are considered.

We have undertaken a study of high work function (φ) surfaces as part of an ongoing project searching for efficient target materials for use in Hyperthermal Surface Ionisation (HSI), a new mass spectroscopy ionisation technique. HSI relies on high work function surfaces for the production of positive ions. Polycrystalline metals as Re, W, Mo and Pt are particularly interesting materials in this respect as oxidation substantially increases their φ. We present and discuss the following experimental evidence: a) the magnitude and sign of φ changes in terms of adsorbate induced dipoles, b) the effect of molecular hydrogen exposure on the clean surface, and c) the effect of subsequent oxygen exposure.

Using a novel UHV Scanning Kelvin Probe we have followed the oxidation kinetics of polycrystalline metals at different temperatures and examined the effects of oxidation, flash annealing and sputter-anneal cleaning cycles via high-resolution φ topographies. Our results indicate in particular Re as a suitable HSI target material exhibiting a φ increase of 1050 meV at 300 K increasing to 2050 meV at 900 K. Sputter-cleaned surfaces exhibit a dramatic change in the second oxidation phase.

We have also examined φ changes associated with N2O and CO2 on Tungsten and Molybdenum. We observe that atomic oxygen gives similar results to O2 but has a much lower initial sticking coefficient. We report that CO2 actually lowers the φ for substrate temperatures under 650 K, the peak work function changes occurs at 850 K and is approximately 1/3 the height of the O2 or O peak.

PtMn is one of several candidate antiferromagnetic materials for biasing of spin valve giant magnetoresistive (GMR) sensors used in magnetic recording heads. The as-deposited crystal structure of PtMn is face-centered cubic, which is not antiferromagnetic, and it is commonly annealed to transform it to the ordered face-centered tetragonal structure, which is antiferromagnetic. The changes in the thin film stress during this transformation can be up to 1.5 GPa in magnitude. In this work, the stresses in sputter-deposited, PtMn/CoFe bilayers were measured during annealing using a laser-based wafer curvature technique. During annealing, the stress initially increases before approaching a constant level. This behavior was examined for samples with a range of PtMn compositions and varying degrees of PtMn {111} texture. Both the magnitude and rate of change of the stress are sensitive to the composition of the films, but are relatively insensitive to the film texture. These results are discussed in terms of the binary alloy phase diagram.

The growing interest in the behavior of magnetic thin films on semiconductor substrates is due in part to their potential application in spin-sensitive heterostructure devices. High-quality epitaxial Fe(001) thin films can be grown on GaAs(001) substrates because of the small lattice parameter mismatch (−1.4%). Magnetic measurements performed on Fe films thinner than 3 nm have shown that such films exhibit an in-plane uniaxial magnetic anisotropy although an ideal bcc Fe(001) film should have fourfold symmetry. The source of this uniaxial component remains an open question and one of the mechanisms which may contribute to this is the epitaxial strain, through magnetoelastic coupling. Very small strains anisotropies are able to modify the magnetic anisotropy of iron thin films. Moreover the sign and magnitude of the magnetoelastic coupling seem to depend on the film thickness or film strain [1]. In this study, the strain tensor components in two Fe thin films (1.7 and 3.0 nm thick) has been measured by XRD. The magnetic free energy has been derived, using the strain tensor components.

We discuss the application of x-ray scattering and fluorescence to the problem of unravelling the relationship between the structural and magnetic properties of magnetic multilayers. Particular attention is paid to the use of grazing incidence diffuse scatter to determine the compositional gradient, out-of-plane roughness amplitude, in-plane correlation length and fractal parameter of buried interfaces. Anomalous scattering provides information on the local environment of specific atoms and grazing incidence fluorescence is a depth -sensitive probe of chemical composition. We present examples indicating the sensitivity limits and the reproducibility of the techniques, all from multiple layer structures of magnetic metals.

FePd(001) thin films have been grown by the molecular beam epitaxy (MBE) technique. At room temperature, these films are chemically disordered whereas at 350 °C a well ordered L10 structure is found with the c-axis oriented in the growth direction. By combining RHEED, STM and Auger measurements, it is suggested that ordering occurs at the growing surface by the development of bi-atomic steps of the ordered structure. We have put in evidence that the surfactant behavior of the Pd atoms is mainly involved in the ordering process and selects the single orientation of the c-axis. For intermediate temperatures between RT and 350 °C, TEM and X-rays have evidenced a pseudo-periodic arrangement of anti-phased domains having a columnar shape. The variation of the long-range order parameter is related to the average size of these ordered domains.

The deposition rate of titanium films plays a determining role for possible fabrication schemes of metallic SET structures. Depending on this rate the resistivities display a striking difference in their temperature dependence which is attributed to their different crystal structure as analyzed by transmission electron-beam microscopy. In addition a sharp rise in resistivity occurs below a critical thickness in films deposited at slow rates. This sharp increase can be used in combination with a step induced thinning to form tunnel junctions for single electron transistor structures.

Cu-Al alloys have been recommended for application as the diffusion barriers/adhesion promoters for advanced copper based metallization schemes. This approach to barrier formation is to generate an ultra-thin interfacial layer through Cu alloying without significantly affecting the resistivity of Cu. In this paper the microstructure of the bilayers of Cu/Cu-5 at%Al and Cu-5 at%Al/Cu sputter deposited on SiO2 before and after thermal annealing is investigated by transmission electron microscopy (TEM). Interfacial layer is observed in both cases. The variation of the resistance of the Cu-Al alloy film is consistent with its microstructure. The x-ray diffraction (XRD) spectra of Cu-5 at%Al on SiO2 shows that the addition of Al into Cu intends to favor the Cu (111) texture. These results will be presented and discussed showing that films of Cu doped with Al appear to act as a suitable barrier and adhesion promoter between SiO2 and Cu.

Cu/Ni (001) multilayers have been grown by molecular beam epitaxy at room temperature. In-situ electron diffraction and curvature measurements performed during the growth are presented. The average lattice parameter in the equiatomic multilayers evolves gradually towards the alloy lattice parameter. The in-plane lattice parameter of both Cu and Ni evolves continuously towards the bulk lattice parameter with no evidence of pseudomorphic growth. The combination of diffraction and curvature measurements suggests that the Ni on Cu interface is diffuse. This is attributed to the surfactant behaviour of Cu. This results shed new insights into the interesting magnetic properties of Ni films on Cu (001).

We studied long-range orientational ordering in polycrystalline Au films (10 nm - 30 nm) that are evaporated at oblique incidence onto a glass substrate at room temperature. By measuring the averaged optical second-harmonic response from the films over a 6-mm diameter region, we observed a transition from the expected in-plane mirror symmetry at 10 nm to a surprising three-fold in-plane rotational symmetry at 30 nm. X-ray pole figure analysis performed on these films showed the strong <111> fiber texture typical of fcc films, but with a restricted, three-fold symmetric, distribution of crystallite orientations about the fiber axis.

In this paper, the different applications of Raman spectroscopy for the study of thin films is briefly discussed, using examples from microelectronics. Special attention is given to the application of micro-Raman spectroscopy for the measurement of local stress in and near films.

Mo/Ni multilayers are investigated by x-ray diffraction and Brillouin light scattering before and after ion induced stress relaxation and mixing. Study of the evolution of interplanar distances in both layers as a function of the period exhibits a strong anomaly of the Mo (110) distance (in the growth direction) that can be correlated with the elastic anomaly. The very low interplanar distance in the molybdenum layers found after stress relaxation seems to favor an explanation of this behavior based on the diffusion of Ni in the Mo layers during the growth.

The stress evolution during silicide formation from thin metal films on Si substrates is not well understood. It requires a detailed knowledge of the mechanical properties of each substance, i.e. metal, silicide(s) and Si, in the reacting system. In situ curvature measurement generally gives access to the overall force in the layered stack, whereas in situ X-ray diffraction (XRD) provides information about the mechanical strain in each crystalline sublayer. In this study, we performed both in situ XRD and curvature measurements on the Pd/Si(001) system. From both measurements, we found out that the in-plane strain in the metal and in the silicide is compressive. Whereas it decreases all along the solid-state reaction for the silicide, it slightly increases for the metal. We then compared our results with the qualitative model proposed by Zhang and d'Heurle. This model suggests a high compressive stress in the silicide at the very first stage of the reaction. This is in good agreement with our experimental results. Finally, the measured strains were then translated into force per unit width and compared to in-situ curvature measurement results. A good qualitative agreement between these two different measurements was also found.