We report a study of the microstructure and surface morphology of co-deposited Al-Ge films. At 200 °C and above, the terminal solid solutions are obtained, whereas at lower temperatures, metastable amorphous or crystalline phases coexist with the Al-rich terminal phase. For film thickness below 200 nm, lateral phase separation is observed with surface grooving which reflects the bulk microstructure. Analysis of the data with a model for the diffusion process shows that the results are consistent with a surface diffusion mechanism. For thicker films, there is a transition into a layered microstructure in which Al segregates to the surface. This transition is explained in terms of the surface and interfacial energies of the phases.

This paper discusses the variation in microstructures encountered during the separate depositions of boron nitride (BN) and aluminum nitride (A1N) as well as during the codeposition of BNߝA1N dispersed phase ceramic coatings. This combination was chosen in order to take advantage of the self lubricating properties of hexagonal BN along with the hard, erosion resistance of A1N. Films were characterized using scanning and transmission electron microscopy (SEM and TEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD).

A range of coating microstructures are possible depending on the conditions of deposition. The best films produced, in terms of hardness, density, and tenacity, were a fine mixture of turbostratic BN and preferentially oriented A1N whiskers aligned with the whisker axis perpendicular to the substrate surface as seen by both electron microscopy and x-ray diffraction.

Silicon carbide was deposited from methyltrichlorosilane onto polished polycrystalline SiC substrates at reduced pressure, and the resultant surface morphology was characterized by analyzing the angular spectrum of scattered light which was generated with a He-Ne laser. Light-scattering analyses incorporating specific nucleation and growth models were developed. With these methods, it was possible to analyze the angular scattering spectra and directly measure the nucleation and growth rates. These results were verified by using image analysis to quantify the number and size distribution of surface features that were observed with scanning electron microscopy. The nucleation and growth rates that were obtained by fitting the models to the image-analysis results were in good agreement with the rates obtained from the light-scattering.

An investigation of undoped LPCVD polycrystalline silicon films deposited at temperatures ranging from 605 to 700 C and silane pressures from 300 to 550 mTorr revealed large variations in stress with processing conditions and a correlation between stress and texture. TEM and HRTEM analysis show that morphology differences also exist. At lower temperatures (≈605 C) and higher pressures (≈400 mTorr), the films appear to deposit in an amorphous state and crystallize during the deposition to form microstructures characterized by equi-axed grains, tensile residual stress, and a texture with {110} and {11/} (/=2 or 3) components. Higher temperatures (between 620 and 650 C) produce films that nucleate at the Si02 interface, creating a {110} oriented columnar microstructure. At 700 C, the grains are still columnar, but the dominant texture is {100}. Films deposited at temperatures greater than 620 C exhibit compressive stress, and some contain regions of hexagonal silicon. This paper proposes possible causes of the varying stresses, textures, and microstructures in the films.

Defects created by ion irradiation can enable new modes of microstructural development at interfaces and surfaces in semiconductor thin films. Two examples are described. First, novel kinetic paths for microstructural evolution via MeV ion beam modification of amorphous-crystal interface motion in Si are discussed. At intermediate temperatures, amorphous layer formation is initiated at interfaces such as surfaces and grain boundaries in polycrystalline Si. Irradiation at higher temperatures during the early stages of Si crystallization leads to a significant enhancement of the crystal nucleation rate, while nearly complete suppression of crystal nucleation during crystal growth can be achieved by a cyclic irradiation-induced amorphization and thermal growth process. Second, a new development in misfit strain accommodation in epitaxial semiconductor films is described in which ion-induced injection of point defect complexes can produce coherent, uniformly strained epitaxial thin films. Measurement of strain in epitaxial films can be used to distinguish between surface and sub-surface atomic displacements generated by a low energy ion beam.

The development of microstructure in metal films deposited by ion-assisted evaporation has been studied by transmission electron microscopy (TEM). Films of Ni, Co, and Fe of about 350 to 500 nm thickness were deposited by electron beam evaporation with concurrent argon ion bombardment during growth. Films grown at high ion/atom ratios develop compressive stress as revealed by lattice dilatation. The trends in grain size, orientation, and shape as a function of ion bombardment are documented by TEM.

Thin Fe films, 1 nm to 90 nm, have been grown on GaAs (100) substrates in ultra high vacuum, base pressure = 2×l0−8 Pa. The growth of the films has been followed with Auger electron spectroscopy and a recently developed in-situ UHV M/H hysteresis loop tracer. The Auger signal provides an indication as to when the Fe covers the GaAs substrate or when it clusters into three dimensional islands. The magnetic hysteresis loop tracer provides the coercivity and the saturation magnetic moment, from which the saturation magnetization or average film thickness can be obtained. The coercivity of thin films is sensitive to structure, strain, and to the grain size, in analogy to its sensitivity to particle size for small particles. The data show that the coercivity, Hc, as a function of film thickness, is very sensitive to the annealing procedures and to the resulting morphology, continuous versus local clustering of the iron film. Under proper conditions a clear maximum in Hc versus film thickness is observed for these films near 5 nm thickness, in analogy to three dimensional small particle curves.

Aluminum films 1pm in thickness are deposited by sputtering and by partially ionized beam (PIB) deposition. In the as-deposited condition, the sputtered film has a weak texture while the PIB film has a very strong {111} fiber texture. Annealing at temperature between 250°C and 400°C for 0.5 hr induces grain growth accompanied by texture evolution. These aluminum films are characterized by an {111} texture superimposed on a random grain distribution. When the {111} component dominates as in the PIB condition, little texture evolution accompanies grain growth at successively higher temperatures. When the {111} component is weak, the random component decreases at the expense of a strengthening {111}. Grain growth kinetics are similar for both cases.

A thermal spike model has been developed to describe the phenomenon of ion irradiation-induced grain growth in metal alloy thin films. In single phase films where the driving force for grain growth is the reduction of grain boundary curvature, the model shows that ion-induced grain boundary mobility, Mion, is proportional to the quantity FD 2/ΔHcoh 3, where FD is the ion and recoil energy deposited in nuclear interactions and ΔHcoh is the cohesive energy of the element or alloy. Experimental grain growth results from ion irradiated coevaporated binary alloy films compare favorably with model predictions.

We present measurements on the intrinsic stress developing during chemical vapour deposition of W and WSi2 from the reaction between WF6 and Si (100). It will be shown that depending on temperature and WF6 partial pressure, three growth modes, corresponding with three different stress developments, can be distinguished. The results can be explained with three basic processes. The intrinsic tensile stress during the deposition of self limited W can be as high as 2 GPa.

Large diamond particles up to 30μm in diameter have been deposited on W wire tips using Microwave Plasma Chemical Vapour Deposition. Raman, SEM and TEM investigations were all carried out on a single particle. Large growth steps were observed on (100) facets but were absent on the (111) facets. Raman measurements indicated greater crystalline quality for (100) than (111) facets. TEM revealed the (111) facets to be covered with small islands of diamond about 10Å high. The dominant defect was found to be stacking faulting on the {111} planes which gives rise to some hexagonal spacings in the electron diffraction pattern. The results suggest that growth in the <111> and <100> directions are driven by different mechanisms.

A high mobility of 390 cm2/Vs was successfully obtained for sputtered films, compared with 100 cm2/Vs for CVD films. Then, structural characterization of laser-annealed sputtered silicon films were performed, and compared with that of CVD films. TEM observations show a structural difference between the two film types. In sputtered films, many fine grain-like regions which have slightly different crystal orientation from surrounding regions are observed. On the other hand, in the CVD films, defects are widely spread over the film. X-ray diffraction, Raman scattering, and SIMS yield almost the same results in both films. The above-mentioned structural difference is thought to be essential to obtain high mobility.

Polycrystalline InSb thin films have been prepared by two-source thermal evaporation method. The as-deposited randomly oriented thin films develop (111) preferred orientation upon heat treatment of different maximum setting temperatures, T(max)s. Under different T(max)s, the elongate (111) grains rotate gradually the direction of the elongation respect to the thermally oxidized Si(100) substrate.

The (111) preferred orientation has been seen from both cross-sectional TEM and X-ray diffraction patterns. The electrical mobility value of the thin film has been measured by the Van der Pauw′s method. A dramatic increase in the electrical mobility from few thousands, for the as-deposited film, to intermediate values of 15,000-30,000 cm2/v-s and the highest value of 36,000 cm2/v-s for thin films subjected to different T(max)s, can be correlated well to the corresponding microstruetures.

Polcrystalline BaTiO3 films have been grown on NdGaO3 [100], SrTiO3 [100] and Si [100] substrates by reduced pressure CVD. The substrate temperature was 1000°C and the total pressure during growth was 4 torr. X-ray diffraction measurements indicate highly textured films on the NdGa03 substrate. The orientation was predominantly [100], accompanied by small quantities of various TiO crystalline phases.

Thin films of BaTiO3 and PZT (lead zirconate titanate, 47%PbTiO3, 53%PbZrO3) have been produced by laser irradiation of the appropriate ceramic targets and deposition of the ejected and vaporized material on planar substrates. The microstructural changes during thermal processing of these films have been studied by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDX), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), x-ray diffraction (XRD), and by measurement of electrical properties. Films have been deposited using both Nd/YAG and excimer lasers and on unheated as well as heated substrates. Excimer films are considerably smoother than the Nd/YAG films, and the uniformity of the as-deposited microstructures is promoted by substrate heating. However, ferroelectric hysteresis loops were only observed for the considerably less smooth Nd/YAG PZT films; thermal treatment did little to improve the smoothness of these films. An excimer BaTiO3 film deposited on a heated substrate showed crystallographic alignment and had a dielectric constant of −100. Efforts are underway to combine the best features of films produced by both methods.

We report on a study of hard amorphous carbon thin films prepared by condensing streams of energetic carbon species, onto a range of substrates maintained at different temperatures. The carbon vapor is generated either by ion sputtering, laser ablation or e-beam evaporation. Spatially resolved electron-energy-loss spectra reveal variations in the films′ microstructure brought about by altering the deposition conditions. We estimate that the density of the different films varies between 2.0 and 3.26 g/cm3. We observe an evolution towards denser films upon increasing incident beam energy, reducing substrate temperature, and increasing substrate thermal conductivity. Low density films contain a predominance of trigonally bonded sp2-hybridized carbon (i.e graphitic carbon) and the highest density films contain a high fraction (∽ 80%) of tetr-ahedral sp3-bonded carbon (i.e. diamond-like).

Diamond films have been synthesized by microwave Plasma Enhanced CVD (PECVD) and permanent magnet induced Electron Cyclotron Resonance (ECR) PECVD of hydrogen diluted methane. The films are characterized by SEM images and Raman spectroscopy. The diamond films grown by ECR-PECVD show clear-cut habits of cubic crystal in SEM images, while the film grown by microwave PECVD are the polycrystalline. A Raman line at 1333cm‒1 and broad band located at ∼1500 cm‒1 were obtained for the films grown by both methods. However, the film grown by microwave PECVD shows a larger broad band which is associated with an sp2-bonded graphitic phase

The influence of amorphization of the Si substrate by Ge+ implantation on the microstructural evolution of CoSi2 thin films has been investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and four-point-probe measurement. While the silicide films formed on unimplanted or recrystallized Si were similar in formation kinetics, microstructure and resistivity, unique features were found for silicide films formed on amorphized Si. The phase transformation to CoSi2 on amorphized Si was considerably accelerated, the silicide grain size was smaller, and the CoSi2/Si interface was much smoother on the amorphized Si. Direct evidence of grain boundary diffusion induced silicide/Si interface roughness was obtained. The origin of the difference in both the microstructure and kinetics on different Si substrates is explained by the latent energy stored in amorphous Si, increasing the silicide nucleation rate. Weak XRD peaks and different texture were found for the CoSi2 formed on amorphized Si. The facts that the dominant diffusing species during CoSi2 formation is Co, and the new phase was developed in an amorphous medium are thought to be responsible for these phenomena.

Integrated circuit fabrication consists of many processing steps: e.g. lithography, etching, implantation and metallization. Some of these processes are combined with thermal processing. Heat treatments require special attention because previous fabrication steps may be influenced: e.g. dopant profiles may be deteriorated. The amount of interference of an annealing step with a former process is determined by the ratio of the reaction rates (and hence by the difference in activation energies).

We find that the density of electronically active defect states, formed close to the Si/SiO2 interface during high temperature oxidation (Tox > 800°C), is proportional to the thickness-averaged stress or strain in the oxide layer. This was established by measuring the midgap interface state density, Dit, and correlating it with: i) a direct measurement of the stress, using a beam deflection technique; and ii) a determination of the oxide strain, using infrared (IR) spectroscopy and a model that relates the frequency of the Si-O bond-stretching vibration to the microscopic strain in the oxide.In addition, the elastic stress at the Si/SiO2 interface has been modified by film deposition onto the SiO2 surface of Si:3N4 film or a variable thickness of an Al gate metal. The additional elastic stress introduced by these depositions did not influence Dit. These observations lead us to conclude that interface traps are generated by “local plastic deformations” that occur during the oxidation process, and are localized in the immediate vicinity of the Si/SiO2 interface.