Comparison of two techniques for reliable characterization of thin metal-dielectric films

In the present study we determine the optical parameters of thin metal-dielectric films using two different characterization techniques based on nonparametric and multiple oscillator models. We consider four series of thin metal-dielectric films produced under various deposition conditions with different optical properties. We compare characterization results obtained by nonparametric and multiple oscillator techniques and demonstrate that the results are consistent. The consistency of the results proves their reliability.     

The characterization of annealing in thin metal films using the Mayadas-Shatzkes theory

A technique suggested by Mola and Heras of analyzing thin film size effect data is used to characterize the structure of thin polycrystalline metal films. A linear least-squares analysis of the product of resistivity and thickness versus thickness allows a consistent determination of the size effect parameter α. Annealing studies (130–460 K) on gold films (120–1150 Å) yield temperature-independent values of the reflection coefficient both before and after annealing and allow the annealing to be characterized quantitatively.     

Thermophysical properties of thin metal films

A method is proposed for determining thermophysical properties of thin metallic films, using solutions of converse thermal conductivity problems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 1, pp. 130–135, January, 1990.     

Transport properties of thin metal films

The electrical conductivity, thermal conductivity and thermoelectric power of a metal film subjected to the simultaneous action of an electric field and a temperature gradient were calculated. Analytical equations for the electrical and thermal current densities in thin metal films were obtained.     

Thermophysical properties of thin metal films

The article discusses methods and results of comprehensive investigations of the thermal conductivity, thermal diffusivity, heat capacity, and structure of films of metals 10–10² nm in thickness.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 4, pp. 606–613, April, 1980.     

Optical pump-and-probe test system for thermal characterization of thin metal and phase-change films

A single-shot optical pump-and-probe test system is reported. The system is designed for thermal characterization of thin-film samples that can change their phase state under the influence of a short and intense laser pulse on a subnanosecond time scale. In combination with numerical analysis, the system can be used to estimate thermal constants of thin films, such as specific heat and thermal conductivity. In-plane and out-of plane thermal conductivity can be estimated independently. The system is intended for use in research on optical data storage and material processing with pulsed laser light. The system design issues are discussed. As application examples, we report on using the system to study thermal dynamics in two different thin-film samples: a gold film on a glass substrate (a single-phase system) and the quadrilayer phase-change stack typical in optical data-storage applications.     

The adhesion of thin plasma-polymerized organic films to metal substrates

The direct pull method was used to study the adhesion of thin (<1 μm) plasma-polymerized films on metal substrates. Application of this method provides information on the cohesive, as well as the adhesive, properties of these films. After breakage of the films by the pull method, the interface was analyzed by scanning electron microscopy to determine the nature of the breakage at the interface. Electron spectroscopy for chemical analysis was used to determine whether any chemically adsorbed layers of organic films remained after the films had been pulled from the metal substrate. The adhesive or cohesive strengths of plasma-polymerized tetrafluoroethylene and chlorotrifluoroethylene films on 304 stainless steel, aluminum and silver were measured by the pull method. Adhesive strength was found to be higher than cohesive strength for plasma-polymerized tetrafluoroethylene films on the various substrates. The result for plasma-polymerized chlorotrifluoroethylene films was not as expected, indicating that considerable care is required in the interpretation of tensile tests of laminates such as those conducted in this study.     

Electrical properties of thin metal zinc films

Thin metal zinc films 40 to 200 nm thick are deposited by thermal evaporation at room temperature onto glass substrates with a deposition rate of 0.2 to 0.7 nm sec^–1. The electrical resistivity is measured as a function of film thickness, deposition rate and annealing temperature. The experimental results show that electrical resistivity decreases as the film thickness, deposition rate and annealing temperature increase, while the temperature coefficient of resistivity increases with the increase in the film thickness. The calculated values of the activation energy for the conduction electrons increases as the film thickness and deposition rate increase. The well known Fuchs-Sondheimer model is applied for zinc films. The theoretically calculated values for the electrical resistivity and the temperature coefficient of resistivity are in good agreement with the experimental results.     

Spectroscopic ellipsometry of metal phthalocyanine thin films

Optical functions of cobalt phthalocyanine, nickel phthalocyanine (NiPc), and iron phthalocyanine (FePc) have been determined by use of spectroscopic ellipsometry in the spectral range 1.55-4.1 eV (300-800 nm). The samples were prepared by evaporation onto glass and silicon substrates. The optical functions were determined by point-to-point fit. Absorption spectra were also measured. The index-of-refraction data for NiPc and FePc are reported for the first time to our knowledge. Good agreement with the experimental spectra was obtained for all three materials.     

Relaxation of elastoresistance in thin metal films

The change in the resistance of thin evaporated metal films in response to a step strain has been studied. Among the several metal films examined, aluminium and bismuth films exhibited remarkable relaxation, with a time constant of about 1 min at room temperature for a thickness of around 1000 Å. In the case of aluminium films, the time constant was found to decrease with increase of deposition temperature, thickness, annealing period and annealing temperature. In the case of bismuth films, such a clear tendency to decrease was not observed, at least for films thinner than 2 μm. It is suggestef that the resistance relaxation is related to the unusually large stress-strain relaxation which is known to exist in bismuth films. The thickness dependence of the gauge factors of both films is also illustrated.     

Tem characterization of nanodiamond thin films

The microstructure of thin films grown by microwave plasma-enhanced chemical vapor deposition (MPCVD) from fullerene C₆₀ precursors has been characterized by scanning electron microscopy (SEM), selected-area electron diffraction (SAED), bright-field electron microscopy, high-resolution electron microscopy (HREM), and parallel electron energyloss spectroscopy (PEELS). The films are composed of nanosize crystallites of diamond, and no graphitic or amorphous phases were observed. The diamond crystallite size measured from lattice images shows that most grains range between 3–5 nm, reflecting a gamma distribution. SAED gave no evidence of either sp²-bonded glassy carbon or sp³-bonded diamondlike amorphous carbon. The sp²-bonded configuration found in PEELS was attributed to grain boundary carbon atoms, which constitute 5–10% of the total. Occasionally observed larger diamond grains tend to be highly faulted.     

Measurement of transient temperatures of thin metal films

Gold films deposited onto a glass (Herasil) substrate are heated by a short electrical pulse. By measuring the temperature-dependent electrical resistance of the films their temperature rise (about 200 K) is measured as a function of the film thickness (10–90 nm) and of time (20–100 ns). The experimental results agree very well with a one-dimensional heat flow model.     

AFM nanopatterning of transition metal oxide thin films

In this paper we show diverse methods for patterning transition metal oxide (TMO) thin films by Local Anodic Oxidation (LAO) using an Atomic Force Microscope (AFM). At first, direct lithography by current-controlled LAO of TMO thin films and selective wet etching is presented. For insulating films or those whose AFM patterns cannot be selectively removed by wet etching, fabrication of nanomasks is required; thus, the fabrication of Molybdenum and TMO nanomasks is reported. As a further development, we show the AFM fabrication of Mo/poly(methylmethacrylate) (PMMA) nanomasks through multistep processes combining LAO of Mo and dry etching of PMMA. Detailed discussions and comparisons between these methods are presented.     

The electron states of one-dimensional thin metal films

We present a detailed numerical study of the electronic states of a finite one-dimensional array of δ function potentials bounded by square surface barriers which may or may not be symmetrical. We study in particular the surface density of states and its dependence on the surface barriers and on the thickness of the specimen.