Atmospheric pressure micro-thermal-plasma-jet (μ-TPJ) irradiation on amorphous silicon (a-Si) strips and its application to thin film transistor (TFT) fabrication have been investigated. Strip channel with the width smaller than 3 μm is effective to eliminate random grain boundaries by filtering effect. High speed scanning of μ-TPJ suppresses mass transfer of molten Si and generation of in-grain defects. By introducing strip channel, high performance TFTs with a high average field effect mobility (μFE) of 503 cm2V−1s−1 (n-channel) are successfully fabricated with small device to device variation. CMOS shift register fabricated with strip channel TFTs was operated by 5V power supply at 50MHz. These results indicate that μ-TPJ crystallization of strip channel is quite promising for next generation TFT applications.
We fabricated Ni films on a Polyimide (PI) film and an Acrylonitrile-Butadiene-Styrene (ABS) resin substrate using unbalanced magnetron sputtering assisted by inductively coupled plasma. For the PI film, the effect of ion irradiation was controlled by substrate DC bias VS and magnetic flux density toward the substrate BC. For the ABS resin substrate, the effect of ion irradiation was controlled by target DC power PT and magnetic flux density toward the substrate BC. For each substrate, we investigated the effect of ion irradiation on the Ni film structures in detail. The effect of ion irradiation E was estimated by measured physical quantities with respect to sputtered atom flux, ion flux and ion energy. From x-ray diffraction measurement, the crystallite size t(111) increased with the effect of ion irradiation. Minimum film resistivities of 9.0×10−6 and 1.4×10−5 Ωcm were measured for BC=3 mT and E=0.24 on the PI film and BC=5 mT and E=0.98 on the ABS resin substrate, respectively. We conclude that controlling the effect of ion irradiation is effective for high quality Ni film formation on the PI film and the ABS resin substrate.
We have developed PIG plasma CVD to the product stage as a practical system for producing diamond-like carbon (DLC) layers by applying a hot cathode Penning Ionization Gauge (PIG) ion source that can easily obtain a high-density plasma for plasma CVD. DLC layers produced by this system have a high deposition density and adhesion. A special feature is that both a low friction characteristic and resistance to wear are achieved by film nanomultilayering. This paper describes the system and reports tribological characteristics of the film. To measure the friction reducing effect in oil, we also developed a new arc discharge magnetron sputtering system. A carbon nitride (CNx) layer produced with that system has a coefficient of friction that is 40% or more lower than DLC produced by conventional CVD methods. That result is also reported.
Atmosphere control during low-pressure carburizing is important from a quality assurance viewpoint. We have developed a low-pressure carburizing furnace that can be used for mass production, which has an atmosphere control system comprising a thermal conductivity hydrogen sensor and an oxygen sensor. The hydrogen sensor is used for providing an atmosphere control necessary for carrying out both low-pressure carburizing and carbonitriding processes. The oxygen sensor detects air leaks and sooting in the furnace. In this paper, we demonstrate that when the atmosphere during the low-pressure carburizing and carbonitriding processes is controlled using the hydrogen sensor, the amount of carbon and nitrogen infiltrated into the steel parts can be controlled, even if the parameters such as the flow rate of gases, temperature, and the surface area of the parts change.
Thermal spraying technique is often applied to inner parts used for vacuum equipment. Sprayed films have the property to prevent separation of films deposited over inner parts, which in turn prevents dust generation in vacuum equipment and ensures stable operations of vacuum equipment for longer period. Inner parts of vacuum equipment is also subject to a number of surface treatment processes other than thermal spraying before incorporated into vacuum equipment. This article describes surface treatment technologies used for the inner parts of vacuum equipment.
Atmospheric pressure plasma is a powerful tool for various material processing. In this article, development of atmospheric pressure plasmas are reviewed, particularly for glow-like plasma which is characterized by spreading in space and has an advantage applicable to surface treatment. One important issue in application of atmospheric pressure plasma is a large area processing, and as one candidate for the purpose, line-shaped microwave plasma in atmospheric pressure is also reviewed.
A method for quantitatively determining the critical thickness, dcrit., for columnar growth of a CoPtCr-SiO2 granular layer was evaluated. The value of dcrit. can be determined from a plot of the perpendicular magnetic anisotropy energy (Ku) of the layer, Ku×dmag., versus the layer thickness, dmag.. The value of dcrit. reflects the structural uniformity of the layer in the thickness direction, and can be used as an index for choosing suitable deposition conditions and the material for the granular layer. Using the proposed method, columnar growth structures can be analyzed by evaluating their magnetic properties and layer thickness without observing cross-sectional TEM images. This inexpensive and simple method can potentially be used to characterize columnar growth structures on the nanometer scale.