Over the last ten years, surface coating engineering has become a key technology throughout the world, especially due to the successes achieved in the optics and microelectronics sectors. First advances in the wear protection field were attained with coated carbides, indicating a substantial technical and economic potential in these areas.

The development of wear protective coatings often reaches the limits of what is technically possible. For this reason, processes incorporating two different methods and combining the specific advantages of each are increasingly being developed for the deposition of certain coatings. In the study presented here, PVD (Physical Vapour Deposition) technology was combined with laser surface treatment technology to produce amorphous and crystalline SiC coating phases. The objectives of the study were to establish the respective advantages of crystalline and amorphous phases. The amorphous ceramic coating exhibits excellent corrosion resistance, whereas the crystalline phases generally attain higher adhesion and superior stability at high temperatures. There are therefore technical applications for both phases.

This paper describes the classification of existing integration schemes for ferroelectric memories, including both nonvolatile and volatile devices, and the status of device development for CMOS (both SRAM and DRAM architecture), GaAs JFET structures, bipolar, and true ferroelectric FETs (in which the ferroelectric is deposited in the gate region to modify the source-to-drain current when the polarization is reversed). Emphasis in the paper is on electroding, film deposition, drying and baking, and annealing steps.

Pure and doped lead-titanate (PT) and lead-zirconate-titanate (PZT) thin films have been deposited on platinum-coated silicon by rf-magnetron sputtering from pressed powder targets. The films have been deposited without substrate heating. The amorphous films were then annealed in an oxygen flow. The structure of the films is tetragonal or rhombohedral depending on composition. The electrical resistivity, dielectric permittivity, ferroelectric hysteresis and pyroelectric coefficient are reported.

The feasibility of the fabrication of thin film capacitors of Lead Zirconate Titanate (PZT) by reactive DC-Magnetron sputtering, with large switched charge and low leakage current densities for ultra-large scale integration Dynamic Random Access Memory (ULSI DRAM) applications has been demonstrated. As-deposited films were found to be predominantly pyrochlore; therefore, a subsequent phase transformation-inducing thermal processing step was key to obtaining device quality films. The importance of the thermal budget in optimizing the device characteristics of PZT films is discussed. The importance of the role of Pb compensation in lowering the required thermal budget and significantly enhancing device characteristics is shown.

The nanostructure evolution of PZT, PT and T thin films has been studied by high-resolution electron microscopy (HREM) supported by other techniques such as thermal analysis, thermal mass spectrometric analysis and X-ray diffraction analysis. The evolution follows a common progression from amorphous film, to the development of condensed regions that develop crystalline order, to the final polycrystalline oxide thin film. If the precursor gel contains lead, the film develops fluctuating surface “blisters” that evolve to an oxide final product as well. Minor structural and compositional differences exist across the final oxide thin film.

High quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2 ' area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 500°C in films with thickness above 0.36μm.

Metastable pyrochlore structures were observed in films with thickness of 0.16,μm when heat treated at 500 and 600 °C. But these structure did not appear in films with thickness of 0.36μm.The thickness dependencein crystal structure of films was studied by varing the substrate condition and analyzing the interface between the.film and. substrate. In native oxide films on silicon substrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide (cubic property in random network structure).

Capacitance-voltage characterstics of BaMgF4 film deposited in an ion-assisted deposition system shows hysteresis and the direction of hysteresis corresponds to ferroelectric polarization. Electrical characterization of the films shows that these films can be used to implement non-destructive read-out non-volatile ferroelectric memories. These films were found to dissolve in water and other aqueous solutions. In order to overcome this problem, a suitable capping layer like zirconium oxide and amorphous silicon was deposited on BMF films. The shift in threshold voltage did not change significantly due to the incorporation of the capping layer. The shift in threshold voltage was found to be temperature dependent and this might be due to ionic conduction in fluorides.

Dense smooth lead zirconate-titanate thin films have been prepared by excimer laser deposition. The as-deposited films are amorphous as indicated by x-ray powder patterns. Differential scanning calorimetry studies show that the film has a glass transition at 301 °C, and the amorphous to crystalline transformation takes place above 350°C to 650°C. Phase formation as a result of post-deposition heat treatment is described.

Time-resolved micro-Raman spectroscopy is used to follow the amorphous to crystalline phase transformation in sol-gel deposited titania films induced thermally or through the action of applied hydrostatic pressure in a diamond anvil cell. Time-dependent phonon intensities intrinsic to the growing phase are related to the volume fraction of crystallite present at any time. The sigmoidally generated curves can be modeled in terms of modified Avrami ingrowth kinetics in which diffusion of the amorphous phase to the nucleation center is restricted by the morphology of the evolving phase. Phonon frequency and linewidth measurements during the course of the transformation probe changes in film stress and particle size which are used to understand the mechanistics of the transformation. Raman measurements also are used to derive a phase stability diagram for titania films.

The kinetics of oxidation in Yba2Cu3O7-x thin films in the presence of molecular and atomic oxygen ambients have been studied. The resistivity of c-axis, a-axis, and mixed a+c axis oriented films, deposited in-situ by off-axis magnetron sputtering, was measured as a function of time subsequent to a change in the ambient conditions. The oxidation process is shown to be thermally activated and can be characterized by a diffusion model with an activation energy which varies from approximately 1.2eV in the presence of molecular oxygen to 0.6eV for a flux of 2×1015 oxygen atoms/cm2sec. In both cases, diffusivity is found to be insensitive to oxygen stoichiometry, but the rate of oxidation is found to be sensitive to the microstructure and orientation of the films.

The combination of 16O(α, α)16O oxygen resonance measurement and transmission electron microscopy (TEM) provides an unique and effective method to study the kinetics of nucleation and growth of Cu2O phase during reduction. In situ TEM observation showed that isolated and large Cu2O grains emerge from the small CuO grain matrix and the growth of Cu2O grains is linear with time. We propose that the discontinuous morphology of grain growth of Cu2O is due to the migration of the Cu2O-CuO phase boundary induced by oxygen out-diffusion along the moving phase boundary. Based on the classical analysis of phase transformation by Johnson, Mehl and Avrami, the activation enthalpy of nucleation of Cu2O phase in the CuO matrix has been deduced as ΔEn=2.3 eV. The specific interfacial energy between CuO and Cu2O phases has been estimated as 0.5 eV/atom.

The microstructures of reactive sputter-deposited alumina films have been studied by transmission electron microscopy. The as-deposited films contained γ-A12O3 phase in an amorphous alumina matrix. Annealing of the films at 1200° C for 2 h resulted in nucleation and concurrent anomalous grain growth of α-A12O3 in a polycrystaUine γ-Al2O3 matrix which exhibited a layered microstructure and was strongly textured along [001]. The grain sizes of α-A12O3 varied from 3 to 20 μm, while the average grain size of γ-A12O3 was only about 50 nm. It appears that the nucleation kinetics of a-A12O3 was slow. As a result, the abnormal grain growth of α-A12O3 proceeded by consuming surrounding γ-Al2O3 grains. An atomic model is presented to explain the origin of layered structure in γ-A12O3. The nucleation mechanism of a-A12O3 in γ-alumina matrix is suggested. Orientation relationships between γ- and α-A12O3 are reported. The anomalous grain growth of α- A12O3 is discussed in terms of γ/α interface boundary migration.

Three different types of dislocation interactions with NiFe2O4 (spinel crystal structure) precipitates in a NiO matrix have been studied. In the first, the movement of dislocations introduced by room temperature deformation is impeded by the spinel precipitates. Glide dislocations in the NiO with ½<011> Burgers vectors and {011} glide planes cannot pass through the spinel precipitates without forming stacking faults because the perfect NiO dislocations are partial dislocations in NiFe2O4. Many dislocation loops but no stacking faults were observed in the deformed samples indicating that the gliding dislocations formed the loops when they moved past the precipitates. In the second type of interactions, cusps were formed in the spinel-NiO interface at close to the dislocation loops when the sample was heat treated; the cusps indicate preferential dissolution of the spinel. In the final interaction, the dislocations were shown to act as preferential nucleation sites when spinel was precipitated from the NiO matrix. At slow nucleation rates, NiFe2O4 precipitated only on the dislocations; when the nucleation rate was increased, precipitation occurred both on and away from the dislocations. Precipitates which form at a dislocation may contain a stacking fault extending from the partial dislocation to a cusp in the spinel-NiO interface. When this occurred, the stacking faults were observed to be faceted parallel to either {111} or {011} planes.

Effects of heat treatments on the dielectric properties of tantalum oxide thin films(250Å) deposited on the p-Si substrates by RF reactive sputtering were investigated. The leakage current density was considerably reduced from 10-9 to 10-12A/μm2 at an electric field of 2MV/cm after rapid thermal annealing in O2 at 1000°C, while little leakage reduction was observed after annealing at 500°C.

The structural changes of tantalum oxide thin film after annealing were examined using high resolution transmission electron microscopy. The leakage reduction after annealing can be attributed to crystallization and reoxidation of the amorphous tantalum oxide thin film.