Thin Film Fabrication Techniques Research Articles

Composition spread metal thin film fabrication technique based on ion beam sputter deposition

A composition spread metal thin film fabrication technique based on ion beam sputter deposition method was developed. The technique enables us to fabricate any desired part or a complete binary/ternary composition spread metal thin films onto a single substrate by sequentially sputtering different target materials. Composition spread metal thin films can be deposited directly on a dielectric film in patterned electrode shape for C– V and I– V measurements. The system could be especially useful in the search for new multi-component metal gate materials.

Tunable Drug Release from Hydrolytically Degradable Layer-by-Layer Thin Films

The development of new thin film fabrication techniques that allow for precise control of degradation and drug release properties could represent an important advance in the fields of drug delivery and biomedicine. Polyelectrolyte layer-by-layer (LBL) thin films can be assembled with nanometer scale control over spatial architecture and morphology, yet very little work has focused on the deconstruction of these ordered thin films for controlled release applications. In this study, hydrolytically degradable LBL thin films are constructed by alternately depositing a degradable poly(beta-amino ester) (polymer 1) and a series of model therapeutic polysaccharides (heparin, low molecular weight heparin, and chondroitin sulfate). These films exhibit pH-dependent, pseudo-first-order degradation and release behavior. The highly versatile and tunable properties of these materials make them exciting candidates for the controlled release of a wide spectrum of therapeutics.

Advanced techniques for the fabrication of square spiral photonic crystals by glancing angle deposition

Using the glancing angle deposition thin film fabrication technique, it is possible to create tailored, three-dimensional periodic square spiral photonic crystals that exhibit a band of forbidden electromagnetic frequencies related to the dimensions of the nanostructures. Typically, when fabricating square spirals by traditional means, several problems arise due to nonuniform shadowing that results in column broadening and the loss of required periodicity for thicker crystals. Through the use of complex substrate motion that imposes greater restrictions on growth and shadowing, many of these problems have been overcome, in particular through the implementation of two new algorithms: the slow corner and the variable angle post methods. These motion algorithms have been implemented in conjunction with square spiral photonic crystal fabrication to provide more uniform spiral structures along with more stringent periodicity across the crystal that will allow for photonic band gap structures with more ideal characteristics.

Quick-set thin films

Transistors that have active components based on thin films, rather than silicon, are attractive for many applications. The latest thin-film fabrication technique has the potential for industrial-scale production.

Combinatorial Synthesis and Evaluation of Functional Inorganic Materials Using Thin-Film Techniques

AbstractNovel phases of functional inorganic chemical systems can be efficiently explored using high-throughput thin-film fabrication techniques coupled with rapid characterization schemes. High-throughput investigation of thin-film materials has already led to the discovery of new dielectric and magnetic materials. In this article, we review various high-throughput thin-film synthesis/evaluation techniques and discuss examples of exciting discoveries and new applications of combinatorial techniques.

Low Cost, Indigenous, Ultra-Thin HTSC Film Deposition Technique for Device Applications

Low-cost, indigenous, HTSC ultra thin film fabrication technique has been demonstrated. The technique makes use of a simple idea of conversion of a thin layer of copper deficient non-superconducting ‘123’ substrate in to a superconducting phase by copper doping. It gives films of thickness around 20nm and Tc of 92.88K. The XRD patterns of the substrate show the formation of 123 phase in the substrate even with sufficient copper deficiencies. The intensities of peaks which corresponds to ‘123’ phase have found to increase after copper doping.

High Temperature Superconducting Microwave Filters

The design philosophy of high temperature superconducting high Q filter, is discussed. The special design considerations associated with HTS thinfilms such as the effects of kinetic inductance and mutual inductance, film thickness effects, power handling capability, interfacing and packaging techniques etc are discussed. Material selection for the substrate, and HTSC thinfilm fabrication techniques are addressed. Taking the above considerations into account, high Q microwave filters are designed and analyzed. Experimental results of a C-band filter (1% BW) designed on MgO substrate using YBa2Cu3O7-5 thinfilm are presented.

Deposition of indium tin oxide films by laser ablation: Processing and characterization

In this work an indium tin oxide thin film fabrication technique based on pulsed laser deposition is described and the electrical, optical and mechanical properties of the deposited films are reported. Deposition of high quality films on cold substrates was proved. The third harmonic (355 nm) of an Nd:YAG laser was employed to photoablade the indium tin oxide target.

Fabrication of Waveguide Laser Crystals by Laser Ablation Method. Toward the Fabrication of Laser Crystals on Si Substrates.

OEIC (Optoelectronic integrated circuit) which interconnects various optical and electronic elements on thesame substrate, is a promising device in near future. The fabrication method ofoptical waveguides is desirableto be a vapor phase epitaxy and suitable for in situ processing. LPE (Liquid Phase Epitaxy) methods arewidely used to fabricate thin films, but recently much attention has been paid to PLD (Pulsed Laser Deposition) methods in the fabrication of optical thin films with various advantages such as adaptability to in-situ, processing, simple arrangement, stoichiometry of the films, epitaxial quality of complicated compoundmaterials as good as those by MBE (Molecular Beam Epitaxy) and MOCVD (Metal-Organic Chemical Vapor Deposition). In the present paper, it is experimentally shown that this PLD method is very effective andaffordable as fabrication techniques of these optical thin films.

Vapor-Gel Deposition Method for Oxide Thin Films

In this paper, we attempt to formally establish the chemistry of a vapor-gel process for the low temperature deposition of thin films. A number of applications of such a process will be discussed mostly on a theoretical basis, with the exception of one or two particular aspects that we have experimentally demonstrated so far. The essential components of the deposition apparatus will be described in detail along with some discussions on their operation conditions. Finally, we conclude this paper by systematically comparing the vapor-gel method to other well-known thin film fabrication techniques including the sol-gel method.

H 2 sensing behavior of MOCVD-derived SnO 2 thin films

Thin film fabrication techniques have opened a new era for many electronic devices. However, in the field of gas sensors, thin films have not reached their fully developed stages. In this study, the metal organic chemical vapor deposition (MOCVD) technique has been utilized for the deposition of tin oxide (SnO 2) thin films on polished alumina (Al 2O 3) substrates. For the purpose of the microstructure characterization of the films, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES) have been applied. The films were subjected to sensing tests in both dry air and 1% H 2, balanced by dry air, environment in order to investigate their sensing behavior in relation with the microstructure. The films exhibited faceted grains with rough surface morphology and were composed of columnar grains with pore channels along the grains. The maximum sensitivity occurred between 450 and 500 °C with a magnitude of approximately 20.

Thermotracttve Titanium-Nickel thin Films Formicroelectromechanical Systems and Active Composites

ABSTRACTThin films of thermoelastic titanium-nickel are of interest as a material basis for force-producing elements in microelectromechanical systems, and for active phases in mechanically-adaptive composite materials. The successful introduction of this material system into such application areas will depend on development of reliable thin film deposition protocols, together with the refinement of analytical models which successfully predict the response of active microstructures to a variety of dynamic thermal and mechanical stimuli. In the present paper we review some of our recent experimental and theoretical work which bear on these problems. With respect to thin film fabrication techniques we focus on problems of composition control and the manipulation of microstructure, with particular emphasis on opportunities afforded by amorphous precursor phases formed during low temperature processing, and the fine-grained, thermally stable crystalline microstructures obtainable using hot-substrate deposition. The films resulting from either approach retain the important thermomechanical response features of the well-known bulk-alloy system: shape memory and transformational superelasticity. The response can be modeled in terms of a continuum description augmented with internal variables that track fractional partitioning of the material between austenite and variants of the martensite.

Recent new experiments in magnetic thin film fabrication: Plasma nitriding and SAW exciting substrate

The physical properties of plasma and their effects on film structure such as phase and morphology are discussed based on the results of plasma diagnosis for plasma evaporation and sputtering, respectively. α″−Fe 16N 2 films, as an example, are systematically synthesized by using the above two independent methods and the degree of nitriding process of Fe atoms is discussed in connection with the results of plasma diagnosis. A new thin film fabrication technique which uses a substrate excited by surface acoustic wave (SAW) is proposed. The structural and magnetic behaviours of ultrathin metallic films are discussed in connection with the intrinsic film growth mode evaluated from the propagation properties of SAW during the film deposition. Metallic multilayers, Co/Cu, are formed as a function of oscillation amplitude of SAW and the GMR effect is discussed in connection with the change of interface conditions.

Polymeric modulator for high frequency optical interconnects

We describe the fabrication and performance of a thin-film electro-optic Fabry-Perot modulator operating in reflection, at wavelengths compatible with silicon detectors, fabricated on a silicon substrate. A nonlinear polymer is used with a low dielectric constant that permits an electrical bandwidth in excess of 100 MHz with low modulating energy. Existing thin-film fabrication techniques and materials are used to demonstrate device performance. We report modulation of approximately 1.5% and describe foreseen improvements in nonlinear polymers and technology which promise in excess of 5% modulation with a 5 V modulating voltage. >

CuInSe2 Thin Film Modules for Utility Applications

Recent advances in the efficiency and manufacturing technology of CuInSe2 (CIS) thin films demonstrate the opportunity for low-cost large-scale production of photovoltaics for utility applications. Large area (0.4 m2) submodules with 9.7 percent aperture efficiencies yielding 37.8 watts have been fabricated. Thin film fabrication techniques used in the production of modules enable reduced production costs compared with those for single crystal silicon. The performance of 0.4 m2 modules is projected to exceed 50 watts, based on performance achieved to date on 0.1 m2 modules and small area test devices. Preliminary tests packaged (encapsulated and framed) modules show no significant losses after 15 1/2 months of continuous outdoor exposure. Fabrication of 0.4 m2 modules to demonstrate the feasibility of large-scale commercialization of CIS thin film photovoltaics for utility applications is currently under way.

SPUTIERING PROCESS FOR THE MAGNETIC THIN FILM FABRICATION

Physical properties of plasma and its effect on film structure such as phase and morphology is discussed based on results of plasma diagnostic for plasma evaporation and sputtering. Fe-N films, as an example, are systematically synthesize by using above two independent methods referring the results of the plasma diagnostic and magnetic properties of Fe-N films are investigated. New thin film fabrication technique which uses a surface phonon mode of the substrate excited by surface acoustic waves (SAW) is proposed to control the morphology of very thin film.

Fabrication and applications of piezo-and ferroelectric films

Abstract Different thin film fabrication techniques of ferro- and piezoelectric materials is described with special emphasis on rf sputtering. The relative advantages and disadvantages of oxide and metallic targets, and the control of stoichiometry by adjusting the target substrate distance and composition of target is described. The possible applications of ferroelectric films in non-volative memories, pyroelectric detectors, electro- and acousto-optic devices is briefly presented. The applications of these films in the fabrication of integrated Surface Acoustic Wave (SAW) devices on Silicon is discussed in some detail. Theoretical calculations of SAW transduction in layered media is used to compare selected ferroelectric (PZT, PbTiO3. LiNbO3 and BaTiO3) and piezoelectric (ZnO, AIN and CdS) films on silicon for their use in SAW devices.

New thin film fabrication technique using a substrate excited by SAW

A novel thin-film fabrication technique which uses a surface phonon mode substrate excited by surface acoustic waves (SAW) to control the morphology of very thin films is presented. Permalloy films and Co-Cr-Ta films of 300-AA thickness were prepared by DC magnetron sputtering onto LiNbO/sub 3/ single-crystal substrate excited by SAW. By scanning electron microscopy and scanning tunneling microscopy observations, the structure of films was found to be drastically changed by SAW excitations as a function of excited amplitude. Especially at the critical excitation voltage, the film structure consists of a homogeneous grain form, and a very fine grain size is realized. In the Co-Cr-Ta sputtered films fabricated at this critical SAW excitation voltage of 8 V, H/sub c/ takes a minimum value of about 5 Oe, which is two orders lower than that of films fabricated without SAW excitation. The Mo-Permalloy films fabricated at this voltage are stress-free and have excellent soft magnetic properties.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Fabrication of thin-film metal nanobridges

Thin-film fabrication techniques for forming three-dimensional ‘‘point contacts’’ are presented. As-fabricated nanobridges can be modified using electromigration to make the constriction region smaller or dirtier. Scientific applications to quantum transport studies, 1/f noise, and electromigration are discussed.

Comparison of low-voltage field emission from TaC and tungsten fiber arrays

Field emitter array (FEA) devices were constructed using thin-film fabrication techniques based on in situ eutectic composites containing either TaC or NbC fibers in a NiCr alloy matrix. The emission characteristics of the TaC devices were measured and compared to those of W–ZrO2 FEA's. Both devices produced the linear Fowler-Nordheim plots common to all field emission devices; however, the array current density of the TaC FEA's was more than two orders of magnitude lower than that of the W–ZrO2 FEA's. This was primarily due to the lower fiber density and lower field enhancement of the carbide fiber devices. If it were possible to produce cathode geometries comparable to those of the W–ZrO2 FEA's, a theoretical analysis indicates that emission performance of the TaC devices would be superior because of the lower work function of TaC. However, post-emission observations indicated that the carbide fiber emitters failed more readily than the tungsten emitters under comparable operating conditions.