Resistivity Indium Tin Oxide Research Articles

Surface Modification of Poly(Tetrafluoroethylene) Films by Graft Copolymerization for Adhesion Improvement with Sputtered In-Sn Oxides

Surface modification of Ar plasma-pretreated poly(tetrafluoroethylene) (PTFE) films was carried out via UV-induced graft Copolymerization with glycidyl methacrylate (GMA), acrylamide (AAm) and hydroxylethylacrylate (HEA) to improve the adhesion strength with sputtered indium-tin-oxide (ITO). The surface compositions of the graftcopolymerized PTFE films were studied by X-ray photoelectron spectroscopy (XPS). The graft yield increases with increasing monomer concentration and Ar plasma pre-treatment time of the PTFE films. The T-peel adhesion strength was affected by the type of monomer used for graft Copolymerization, the graft concentration, and the thermal post-treatment after ITO deposition. A double graft-copolymerization process, which involved initially the graft copolymeri/ation with AAm or HEA, followed by graft Copolymerization with GMA. was also employed to enhance the adhesion of sputtered ITO to PTFE. T-peel adhesion strengths in excess of 8 N cm were achieved in the ITO graft-modified PTFE laminates. The adhesion failure of the ITO/PTFE laminates in T-peel tests was found to occur inside the PTFE films. The electrical resistance of ITO on all graft-modified PTFE surfaces before and after thermal post-treatment remained conslant at about 30 Ω square, suggesting that the graft layer did not have any significant effect or. the electrical properties of the deposited ITO.

Resistivity and oxygen content of indium tin oxide films deposited at room temperature by pulsed-laser ablation

Transparent, conductive indium tin oxide (ITO) films were fabricated by pulsed-laser deposition on substrates held at room temperature. We investigated the relationship between electrical/optical properties of the films and the material stoichiometry, measured by Rutherford backscattering. The lowest resistivity films (∼4×10−4 Ω cm) have excessive oxygen compared with the stoichiometric composition ITO. After annealing in argon at 400 °C for 1.5 h, the oxygen-to-(indium+tin) ratio approaches the stoichiometric composition of 1.5 and resistivities of annealed samples are ∼2.5×10−4 Ω cm. The room-temperature ITO resistivity dependence on chamber gas pressure is explained in terms of a gas-dynamic model and oxygen content of the film.

Low resistivity indium tin oxide films deposited by unbalanced DC magnetron sputtering

Indium tin oxide (ITO) thin films are prepared on soda lime glass by a DC magnetron sputtering technique having the unbalanced-magnet structure to escape from surface damages. The material properties are measured by the X-ray diffraction meter (XRD) and atomic force microscopy (AFM) scanning. As a result, the (400) peak as the preferred orientation of 〈100〉 direction for ITO thin films is stabilized with the increase of substrate temperature. The surface roughness and film uniformity with a increase of substrate temperature is improved. The best resistivity is 1.3×10 −4 Ω cm on the position of 4 cm from substrate center. Hall mobility and carrier concentration of the ITO thin films are increased with a rising of temperature. The visible light transmission is around 85% at ITO films of 550 nm thickness.

Effect Of Base Pressure In Sputter Deposition On Characteristics Of Indium Tin Oxide Thin Film

AbstractA novel approach to sputter deposit low resistivity indium tin oxide thin films in cost effective way has been made. To reduce the complication of out-gassing from organic substances that are deposited at prior process steps in the flat panel display manufacturing, DC+RF magnetron sputtering was performed with a relatively high base pressure. Introduction of impurity atoms originated from residual air in the chamber into the film produced the change in lattice as well as microstructure of the film. Sputter deposition with higher base pressure resulted in lower resistivity of the film. Increase in the mobility of the carrier resulted in resistivity decrease. Resistivity as low as 1.5×10−4 Ω cm has been achieved with DC 0.67 W/cm2 + RF 0.67 W/cm2 power density and 10−5 Torr base pressure. X-ray diffraction analysis showed as much as 0.2 % increase in lattice constant resulted from higher base pressure sputtering. No further improvement of conductivity was observed for the base pressure over 10−5 Torr, suggesting impurity introduction saturation into the film.

Micrograin structure influence on electrical characteristics of sputtered indium tin oxide films

The relationship between micrograin structures and electrical characteristics of sputtered indium tin oxide (ITO) films was investigated. Micrograin structures were observed by a high resolution scanning electron microscope. Electrical characteristics were evaluated by four point probe resistance measurement and Hall effect measurement. Low resistivity ITO films had domain structures. One domain consisted of many sputter grains having the same orientation. The resistivity decreased with increasing domain size. The domain boundary might cause scattering for conduction electrons. Therefore, larger domain ITO films had a higher Hall mobility. The minimum resistivity was 1.8×10−4 Ω cm, deposited at a sputtering voltage of −250 V and a 250 °C deposition temperature. The electron conduction mechanism in domain structured ITO films was taken into consideration.

Low resistivity indium tin oxide films by pulsed laser deposition

Indium tin oxide films were grown by pulsed laser deposition on glass substrates. The electrical and optical properties of these films were studied. At optimized oxygen pressures, films with resistivity values of 1.4×10−4 and 5.6×10−4 Ω cm were deposited at substrate temperatures of 310 and 20 °C, respectively. Films with a thickness of 180 nm had a transmission of nearly 100% for the wavelength range of 600–800 nm.

Microstructure and Electrical Characteristics of Sputtered Indium Tin Oxide Films

The relationship between microstructure and electron characteristics of indium tin oxide (ITO) films was investigated. The microstructure and resistivity were found to be dependent on the oxygen partial pressure in the sputtering ambient. Lower resistivity ITO films had a domain structure and a small amount of surface roughness. The small roughness and the large size domain structure caused a decrease in electron scattering, and hence an increase in mobility. Crystallinity was also affected by the oxygen partial pressure. For ITO films with a domain structure, the relative x‐ray diffraction intensity of the (440) crystal plane increased.

Large scale and low resistance ITO films formed at high deposition rates

Preparation of low resistance indium tin oxide (ITO) films on large scale glass substrates has been studied for architectural applications. Coating was carried out by an inline-type plasma-enhanced deposition system with multiple low voltage electron beam (EB) sources based on arc discharge. When Ar was used as the arc discharge gas, low resistance (1 ≈ 2 Ω sq −1) ITO films were obtained on a large scale (1.8 m × 3.2 m) float glass substrate at high deposition rate (6000 Å min −1) and low substrate temperature (<200°C). The minimum specific resistivity of the film was 1.7 × 10 −4 Ω cm . In order to increase the deposition rate further, He was used as the arc discharge gas instead of Ar. An extremely high deposition rate of 12 500 Å min −1 with sufficient visible transmission and low resistivity was achieved and a minimum sheet resistance of 0.9 Ω sq −1 was obtained. An architectural monolithic electromagnetic interference (EMI) shielding window was realized with the above technology. The glass with a sheet resistance of 5 Ω sq −1 showed an EMI shielding performance of -30 dB at 1 GHz.

Low resistance indium tin oxide films on large scale glass substrate

Preparation of low resistance indium tin oxide (ITO) films on large scale glass substrate has been studied for architectural applications. Coatings were carried out by a plasma enhanced deposition technique using sintered ITO pellets as the starting material and high deposition rate of more than 4000 Å/min was achieved. Scanning tunneling microscopy observation revealed that surface morphology of the thick (about 1 μm) film was strongly dependent on the substrate temperature. Crystallinity and electrical properties were also dependent on the temperature and closely related to the surface morphology. The films deposited on 125 °C substrate were composed of a mixture of amorphous and polycrystalline phases and showed a hazy appearance caused by light scattering at the rough surface. The polycrystalline ITO films with a clean and transparent appearance as well as the minimum resistivity of 1.7 × 10−4 Ω cm were obtained on 180 °C substrate. Coatings on architectural size glass substrate (1.8 m×3.2 m) were carried out and minimum sheet resistance of less than 1.25 Ω/sq was obtained. Sheet resistance less than 2 Ω/sq was observed over 88% of the surface area. The transparency and durability of the film were confirmed to be enough for practical use.

7183. Low resistivity indium-tin oxide transparent conductive films. I. Effect of introducing H 2O gas or H 2 gas during direct current magnetron sputtering : S Ishibashi et al, J Vac Sci Technol, A8, 1990, 1399–1402

7183. Low resistivity indium-tin oxide transparent conductive films. I. Effect of introducing H 2O gas or H 2 gas during direct current magnetron sputtering : S Ishibashi et al, J Vac Sci Technol, A8, 1990, 1399–1402

Indium-tin oxide deposition by d.c. reactive sputtering on a low softening point material

The resistivities of indium-tin oxide (ITO) films produced by d.c. reactive magnetron sputtering and subsequently air baked were determined over a range of deposition rates and oxygen flow rates. The dependence of resistivity on deposition rate and oxygen flow rate of ITO sputtered film on glass formed a family of straight lines of constant resistivity emanating from the origin. These lines of constant resistivity were used to provide the form of the boundaries of the operating window for low resistance ITO films deposited on fused, pigmented glass frit substrate with a softening point (370 °C) lower than the air-bake temperature (490 °C) used to convert the sputtered ITO from a soft, dark film to a hard, transparent film. Inside the boundaries the air-baked ITO formed low resistance, conformal films. Outside the boundaries at higher deposition rate:oxygen flow ratios the air-baked film would fold (buckle) along with the underlying frit glass substrate to form higher resistance films. At lower deposition rate:oxygen flow rate ratios the air-baked films would crack along with the underlying frit glass substrate to form higher resistance, sometimes electrically open films.

Low resistivity indium–tin oxide transparent conductive films. II. Effect of sputtering voltage on electrical property of films

A low resistivity and high transmittance Sn doped In2O3 (ITO) film was formed on a glass substrate by dc magnetron sputtering and lower sputtering voltage gave a lower resistivity film. At a sputtering voltage of −250 V, the resistivity obtained was 5.0×10−4Ω cm for room temperature substrate, 2.0×10−4Ω cm for 160 °C substrate, 1.9×10−4Ω cm for 200 °C substrate, and 1.2×10−4Ω cm for 460 °C substrate. At a sputtering voltage of −80 V, the resistivity was 1.3×10−4Ω cm for 200 °C substrate. A measurement of Hall effect shows that the decreased resistivity by lower sputtering voltage is not caused by the Hall mobility but by an increased carrier concentration.

Low resistivity indium–tin oxide transparent conductive films. I. Effect of introducing H2O gas or H2 gas during direct current magnetron sputtering

When an inline sputtering system is used to make conductive transparent ITO film by the direct current (dc) magnetron sputtering method, it was found that the partial gas pressure of H2O affected the properties of deposited films. When the substrate temperature is at or below 200 °C, the control of H2O partial gas pressure is especially important. Using room temperature substrates, an addition of 2×10−5 Torr of H2O in the sputtering process could form ITO films with good repeatability at a low resistivity of 6.0×10−4 Ω cm. By adding H2O gas, it was possible to solve the issue of increased resistivity in thicker films. The films with added H2O gas have H element immersed into the film and have high carrier concentration. Film transmittance stayed constant with or without H2O gas addition. Similar effect was observed by adding H2 gas instead of H2O gas.

The effect of gas atmospheres on resistivity of indium tin oxide films at high temperature

The effects of heat treatment in Q2, O2 and N2, and Ar gases on the high temperature (500‡ C) electrical resistivity of indium tin oxide (ITO) film 52 nm thick prepared by chemical spray pyrolysis method were studied. The partial oxygen pressure effect on the resistivity was found to be\(P_{{\text{O}}_{\text{2}} }^{1/5}\) to\(P_{{\text{O}}_{\text{2}} }^{1/3.5}\). The resistivity changes for cyclic exchange of O2 by Ar gas at 500‡ C. These lead to the conclusion that chemisorption of oxygen atoms in the film surface is dominant for this thin film, for thicker films such as 640 nm oxygen diffusion is found to occur. The Langmuir model of the monolayer isothermal adsorption of oxygen atoms in the surface is applicable to the rapid change of resistivity.

In Situ Preparation of Undoped p‐Type CdTe by Cathodic Electrochemical Deposition

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