Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)

DOI： 10.11470/jsapmeeting.2018.2.0_1352

CiNii Research

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.tsf.2016.12.010

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.12693/APhysPolA.131.463

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Language：Japanese   Publishing type：Research paper (other academic)

DOI： 10.14886/sssj2008.36.0_368

CiNii Article

Other Link： http://ci.nii.ac.jp/naid/130005175806

Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1541/ieejeiss.134.1663

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Language：Japanese   Publishing type：Research paper (scientific journal)

This paper presents a Ku-band low-noise block that includes a PLL with very low susceptibility to power supply in a 0.18µm CMOS technology. The front-end down-converts the input signal from the Ku-band (12∼18GHz) to the IF (∼2.1GHz). The fully integrated LNB is dedicated to both satellite receivers and microwave link products. The VCO that includes full differential varactor shows a very low supply sensitivity (Kpss=-0.18 [%/V]) that can eliminates on chip voltage regulator. The LNB performances include 28.2dB gain, -19.3dBm IIP3, 2.5dB NF, and -107dBc/Hz phase noise at 1MHz offset. The front-end consumes 364mW from a 1.8V supply. The core size is about 0.95×2.3 [mm²].

DOI： 10.1541/ieejeiss.134.1656

CiNii Article

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Language：Japanese   Publishing type：Research paper (other academic)

We have studied the silicon carbon nitride (SiCN) film by hot-wire CVD (HWCVD) method which is possible to deposit films with low temperature in large area.This report describes the characteristics of SiCN films, such as peel-strength, hardness, and a coefficient of friction, for the purpose of utilizing a SiCN film in the machining field.

DOI： 10.11522/pscjspe.2012A.0.313.0

CiNii Article

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)

There are a lot of demands for the semiconductor manufacturing process of large-scale integrated circuit(LSI) and LSI package. Especially, low temperature processes for surface cleaning are strongly required. In this paper, we introduce a novel cleaning technology of various metals using atomic hydrogen generated by a heated catalyzer, hot wire (HW) method. In the case of solder bump cleaning in semiconductor packaging, the oxide layer on the Sn surface was completed reduced, and it was confirmed the effectiveness in improving the flip-chip bonding by the atomic hydrogen treatment. In the case of Cu nano ink-jet wiring, the resistivity was drastically decreased by the atomic hydrogen treatment.

DOI： 10.1380/jsssj.31.196

CiNii Article

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Language：English   Publishing type：Research paper (international conference proceedings)

The demand for high-density mounting increased because of the miniaturizing of a variety of electronic equipment such as personal computers and cellular phones. In response, the use of packaging methods such as flip-chip bonding has also increased to meet this demand. However, during the soldering process, the presence of oxides on the solder bump surface can obstruct the interconnections because oxides with a high melting point do not melt during the process. Methods for removing oxides from the solder bump surface have been developed. In this paper, we propose a novel oxide reduction method for the solder bump surface. This method uses hydrogen radicals generated by a heated catalyzer consisting of a tungsten wire. We have successfully demonstrated that the removal of oxides from the solder bump surface is possible by this treatment. Furthermore, we have verified that this method is effective in improving the reliability of flip-chip bonding without flux.

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.apsusc.2009.05.098

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Language：English   Publishing type：Research paper (scientific journal)

Novel materials and a metallization technique for the printed electronics were studied. Insulator inks and conductive inks were investigated. For the conductive ink, the nano-sized copper particles were used as metallic sources. These particles were prepared from a copper complex by a laser irradiation process in the liquid phase. Nano-sized copper particles were consisted of a thin copper oxide layer and a metal copper core wrapped by the layer. The conductive ink showed good ink-jettability. In order to metallize the printed trace of the conductive ink on a substrate, the atomic hydrogen treatment was carried out. Atomic hydrogen was generated on a heated tungsten wire and carried on the substrate. The temperature of the substrate was up to 60 °C during the treatment. After the treatment, the conductivity of a copper trace was 3 μΩ cm. It was considered that printed wiring boards can be easily fabricated by employing the above materials. © 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2009.05.134

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：Japanese   Publishing type：Research paper (other academic)

DOI： 10.11486/ejisso.23.0_54

CiNii Article

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Language：English   Publishing type：Research paper (international conference proceedings)

The deposition characteristics of carbon film on EUV mask surface, the impact of carbon deposition on lithography performance, and cleaning of deposited carbon film on EUV mask are studied. The density of the carbon film was found to be nearly half of that of graphite by X-ray reflectivity measurement. The impact of carbon deposition on the lithography performance was simulated by SOLID-EUV. The CD variation by carbon deposition on the mask depends on the deposition profile on the absorber pattern. Intentionally created contaminated masks were treated by a cleaning process using atomic hydrogen. The cleaning efficiency and durability of film materials are discussed.

DOI： 10.1117/12.772412

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)

The reduction of various metallic oxides was examined. Atomic hydrogen generated on a heated tungsten catalyzer was used for reduction. It was found that Cu, Ru, Nb, Mo, Rh, Pd, Ir and Pt oxides can be reduced by irradiation with atomic hydrogen. The activation energy for oxide removal was examined and it was found that the values were very small, 10- 2 to 10- 4 eV. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2007.06.094

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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)

DOI： 10.4028/www.scientific.net/AST.54.223

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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)

Scopus

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Language：English   Publishing type：Research paper (international conference proceedings)

DOI： 10.1117/12.711998

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1143/JJAP.46.L633

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (international conference proceedings)

DOI： 10.1016/j.tsf.2005.07.098

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

The reduction of Ru oxide was examined as a way of cleaning the cap layer of multilayer mirrors in extreme ultraviolet lithography (EUVL). Ru deposited on a Si surface was oxidized using electron cyclotron resonance (ECR) O2 plasma, and then treated with atomic hydrogen generated with a hot tungsten wire. An analysis of the surface composition by x-ray photoelectron spectroscopy and Auger electron spectroscopy revealed that atomic hydrogen removed the Ru oxide resulting from the ECR O2 plasma treatment. Additionally, atomic force microscopy observations showed that this treatment caused no increase in the surface roughness of the Ru. This indicates that the surface oxidation of EUVL mirrors is reversible, and can largely be eliminated by using atomic hydrogen and the proper cap layer. © 2005 American Vacuum Society.

DOI： 10.1116/1.2130356

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Language：English   Publishing type：Research paper (international conference proceedings)

A rapid, damage-free method of removing carbon contamination from EUV multilayer has been developed that employs atomic hydrogen generated by a heated catalyzer consisting of a W wire. Test samples were prepared by contaminating Mo/Si multilayers with carbon using EB or synchrotron radiation (SR). The insertion of a thermal shield between the catalyzer and a sample prevented radiant heat from the catalyzer from damaging the sample during cleaning. Ex situ XPS measurements and measurements of the thickness of the carbon layer with optical thickness measurement systems showed that the new treatment completely removes carbon from multilayers. The EUV reflectivity of multilayers was measured before and after cleaning to assess any resulting damage. It was found that cleaning changed the reflectivity and the centroid wavelength only marginally, within the measurement error.

DOI： 10.1117/12.601136

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Language：English   Publishing type：Research paper (other academic)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1143/JJAP.44.1943

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Silicon nitride (SiNx) films were deposited on Si and polycarbonate (PC) substrates at temperatures below 100°C by a catalytic chemical vapor deposition (Cat-CVD) method. By adding H2 to source gases, SiH4 and NH3, it was possible to prevent the deterioration of film qualities in low-temperature deposition /rocesses. H atoms produced from H2 are effective for increasing the film densities and improving passivation properties. The water vapor transmission rate of SiN x films on PC substrates deposited at 80°C was lower than 0.3g/m2day; the detection limit for a cup method. It is concluded that the Cat-CVD method with H2 dilution is a promising technique for preparing highly moisture-resistive SiNx films at low temperatures. © 2005 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.44.1923

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1143/JJAP.43.L1546

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1143/JJAP.43.L1362

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Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)

原料ガスに非爆発原料で有機液体原料であるヘキサメチルジシラザン(HMDS)を用いたホットワイヤーCVD法でSiCN膜を堆積した。HMDSのみでも堆積は可能であり、NH_3の添加とその流量によってSiCN膜の化学組成が制御できることが明らかとなった。

CiNii Article

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (international conference proceedings)

SiNx films prepared by catalytic chemical vapor deposition (Cat-CVD) are applied to passivation and antireflection coating for crystalline Si solar cells. SiNx passivation by Cat-CVD with or without nitridation before SiNx deposition was examined. Both quite high carrier lifetime of 600 μs and low surface recombination velocity of 20-30 cm/s were obtained and these values were comparable to those obtained using remote plasma-enhanced chemical vapor deposition. Successive in-situ exposure of NH3-decomposed species after SiNx deposition also reduces the surface recombination velocity.

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This paper reports about the interface of silicon nitride (SiNx) formed on Si(100) prepared by combination of catalytic-nitridation and catalytic-vapor deposition method in a catalytic chemical vapor deposition system. It is found that flat interface of SiNx/Si(100) is formed by inserting nitridalion layer before growing the SiNxfilms.

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The coverage properties of silicon nitride (Si3N4) films prepared by the catalytic chemical vapor deposition (Cat-CVD) technique were systematically studied. By increasing the catalyzer-substrate distance, the coverage was improved from 46 to 67% on a 1.0-μm line and space pattern. The etching rate of Cat-CVD Si3N4 film measured using 16BHF solution was independent of the deposited position of the micro-patterns deposited, and was approximately 3 nm/min, one order of magnitude lower than that of plasma-enhanced CVD (PE-CVD) Si3N4 film. This means that Cat-CVD Si3N4 films are denser than PE-CVD Si3N4 films, and that the quality at the side wall is equivalent to that on the top surface. That is, Cat-CVD Si3N4 films show a passivation effect, which was excellent, even at the side wall of micro-patterns. These results suggest that Si3N4 films prepared by Cat-CVD are suitable for the passivation films in microelectronic devices having a step configuration, such as TFT-LCDs and ULSIs. © 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0040-6090(03)00100-7

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Language：English   Publishing type：Research paper (international conference proceedings)

DOI： 10.1016/S0040-6090(03)00129-9

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (conference, symposium, etc.)

DOI： 10.1016/B978-044451339-7/50009-X

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.3131/jvsj.46.92

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Removal of various kinds of photoresists, using atomic hydrogen generated by a heated tungsten catalyzer, is investigated. It is found that the photoresist removal is possible for any photoresists. In addition, it is found that the photoresist implanted with doses as high as 1 × 1016 cm-2 can be removed completely. Moreover, the photoresist inside fine line and space patterns can be also removed.

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Rapid progresses are achieved in catalytic CVD (Cat-CVD), often called hot-wire CVD, in the past 3-years NEDO national project in Japan. Cat-CVD technology presents many advantages in thin-film formation processes; high-efficiency of gas use, large-area deposition, no ion bombardment and low-temperature deposition even below 200°C. All of the elemental techniques for the industrially applicable Cat-CVD apparatuses, such as the suppression of the metal contamination, the precise control of the substrate temperature, the life extension of the catalyzer, 1-m size uniform deposition and the chamber cleaning, have been completely developed. Sophisticatedly designed substrate holder with electrostatic chuck and showerhead equipped with catalyzers are both key technologies for these achievements. High reproducibility for film properties is also obtained by controlling the reaction between high-density radicals and chamber walls. Prototype mass-production apparatus for SiNx passivation films in GaAs devices has been already developed and this will be probably the first application of Cat-CVD in industry. These recent movements appear to promise the drastic revolution in semiconductor and flat-panel display industries by introducing Cat-CVD in very near future.

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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1016/S0927-0248(02)00130-7

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Differences between catalytic chemical vapor deposition (Cat-CVD), often called hot-wire chemical vapor deposition, and plasma-enhanced chemical vapor deposition (PECVD) are discussed from the viewpoints of gas-phase kinetics and film properties. Remarkable superiority of Cat-CVD over PECVD is high deposition rate due to high efficiency of gas use. One metre size large-area deposition is also realized using a newly developed gas showerhead equipped with the catalyzer. © 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0042-207X(02)00133-1

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In this paper, a novel method for high-dose ion-implanted photoresist removal using atomic hydrogen generated by a heated tungsten catalyzer is proposed. It is found that photoresist doped as high as 1 × 1015 cm-2 can be removed completely. Quadruple mass spectroscopy detected hydrocarbon fragments during the atomic hydrogen treatment.

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Language：Japanese   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (other academic)

Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1016/S0022-3093(02)00928-6

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Language：English   Publishing type：Research paper (international conference proceedings)

DOI： 10.1109/COMMAD.2002.1237256

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Large grain-size polycrystalline Si (poly-Si) films are obtained on glass substrate by newly developed catalytic chemical sputtering method at low temperatures around 400 C. Si films are also epitaxially grown on (100) single-crystalline Si substrates. In the method Si films are deposited by the chemical transport of SiH4 species generated by the reaction between solid Si target and catalytically generated H atoms. Efficient deposition is realized using the remarkable difference in the etch rate depending on Si target temperatures. That is, SiH4 species are efficiently generated on cooled Si target by atomic-H etching and deposited on substrates with suppressed etching phenomena by heating. Full-width at half maximum of transverse-optical Raman signals originating from crystalline phase for the obtained poly-Si films is narrower than that for poly-Si prepared by excimer-laser annealing. It was noticeable that the grain size exceeds 1 μm for the films with a thickness of about 1 μm. Growth mode of poly-Si films especially in the initial stage is remarkably changed with a difference in the substrate material. It was found that formation of seed layer enhances the growth of poly-Si films on glass substrate.

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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)

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Language：Japanese   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (other academic)

Language：English   Publishing type：Research paper (other academic)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

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© (2001) Trans Tech Publications, Switzerland. Ultra-thin silicon dioxide films can be formed at temperatures as low as 240“C by direct oxidation of Si using active oxygen species generated by catalytic cracking reactions between tungsten and oxygen related gases in a catalytic chemical vapor deposition (Cat-CVD) system. The structural and electrical properties of such films are investigated. It is found that the density of Si atoms in intermediate oxidation states and the density of films determined by etch rate in dilute HF solution are comparable to those of a conventional thermal oxidation at 900°C. The electrical properties and dielectric constant are also comparable to those of thermally oxidized films. The interface state density is as low as 2 × 1011 cm-2eV-1 after rapid thermal annealing at 850°C for 1min in Ar.

DOI： 10.4028/www.scientific.net/SSP.76-77.157

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This paper reports a procedure for low-temperature nitridation of silicon dioxide (SiO2) surfaces using species produced by catalytic decomposition of NH3 on heated tungsten in catalytic chemical vapor deposition (Cat-CVD) system. The surface of SiO2/Si(100) was nitrided at temperatures as low as 200°C. X-ray photoelectron spectroscopy measurements revealed that incorporated N atoms are bound to Si atoms and O atoms and located top-surface of SiO2.

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This paper reports a feasibility of Cat-CVD system for improvement in characteristics of ultra thin gate dielectrics. Particularly, the effects of post deposition catalytic anneal (Cat-anneal) by using hydrogen (H2)-decomposed species or NH3-decomposed species produced by catalytic cracking of H2 or NH3, are investigated. The C-V characteristics are measured by MIS diode for the 4.5nm-thick Cat-CVD SiNx and 8nm-thick sputtered SiO2 for comparison. The small hysteresis loop is seen in the C-V curve of both SiNx and SiO2 films as deposition. However, it is improved by the Cat-anneal using H2 or NH3, and the hysteresis loop completely disappears from the C-V curves for both films. This result demonstrates that the Cat-anneal is a powerful technique to improve quality of insulating films, such as Cat-CVD SiNx and even sputtered SiO2 films. In addition, the leakage current of SiNx films with 2.8nm equivalent oxide thickness is decreased by several orders of magnitude than that of the conventional thermal SiO2 of similar EOT and the breakdown field is increased several MV/cm by Cat-anneal at 300°C.

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)

Ultra-thin silicon dioxide films can be formed at temperatures as low as 240°C by direct oxidation of Si using active oxygen species generated by catalytic cracking reactions between tungsten and oxygen related gases in a catalytic chemical vapor deposition (Cat-CVD) system. The structural and electrical properties of such films are investigated. It is found that the density of Si atoms in intermediate oxidation states and the density of films determined by etch rate in dilute HF solution are comparable to those of a conventional thermal oxidation at 900°C. The electrical properties and dielectric constant are also comparable to those of thermally oxidized films. The interface state density is as low as 2 × 1011 cm-2eV-1 after rapid thermal annealing at 850°C for 1min in Ar.

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Polycrystalline silicon (poly-Si) films arc obtained at temperatures below 400°C by the catalytic chemical vapor deposition (Cat-CVD), often called "hot-wire CVD" method, using two-step deposition (TSD). In TSD, the substrate temperature is changed during deposition from the initial step for a short time of 200 s to the second step of 820 s. A comparative study on the structural properties of Cat-CVD poly-Si films prepared by the TSD method and those of the films prepared by conventional method was carried out using Raman spectroscopy, atomic force microscopy, reflection high-energy electron diffraction and transmission electron microscopy observation. It is found that the surface morphology, grain structure and thickness of the amorphous Si incubation layer are all correlated, and the structures arc changed by TSD method. © 2000 The Japan Society of Applied Physics.

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The feasibility of using ultrathin silicon nitride (SiNx) films, prepared by catalytic chemical vapor deposition (Cat-CVD) method, as an ultrathin gate dielectric is reported. The effects of postdeposition treatments carried out using hydrogen (H2)-decomposed species or NH3-decomposed species formed by catalytic cracking of H2and NH3are also studied. A small hysteresis loop is seen in the C-V curve of as-deposited Cat-CVD SiNxfilms. The leakage current in the case of these films with equivalent oxide thickness (EOT) of 3 nm is slightly larger than that in the conventional thermal SiO2films of similar EOT. However, it is found that the properties of Cat-CVD SiNxfilms are markedly improved by the postdeposition H2or NH3treatments, that is, the hysteresis loop disappears and the leakage current decreases by three orders of magnitude. © 2000 American Institute of Physics.

DOI： 10.1063/1.1319513

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A heated tungsten filament was used to catalyze the gas phase etching of crystalline silicon with hydrogen at a substrate temperature of 200°C for obtaining plasma and contamination free etching. Etch rates, between 100 and 200 nm/min were obtained in a pure hydrogen ambient in the pressure range of 0.01-0.5 Torr. No etching effect was observed in the case of SiO2. No tungsten or other metal and carbon contaminations on the etched silicon surface were detected by X-ray photoelectron spectroscopy.

DOI： 10.1016/S0167-9317(99)00504-3

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

This is to review the present understanding on Cat-CVD (catalytic chemical vapor deposition) or hot wire CVD. Firstly, the deposition mechanism in Cat-CVD process is briefly mentioned along with key issues such as the effect of heat radiation and a method to avoid contamination from the catalyzer. Secondly, the properties of Cat-CVD Si-based thin films such as amorphous silicon (a-Si), polycrystalline silicon (poly-Si) and silicon nitride (SiNx) films are demonstrated, and finally, the feasibility of such films for industrial application is discussed.

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This is to report the feasibility of ultra-thin silicon nitride (SiNx) films, prepared by catalytic chemical vapor deposition (Cat-CVD) method, as an ultra-thin gate insulator. In the Cat-CVD method, the deposition gases such as a gaseous mixture of silane (SiH4) and ammonia (NH3) are decomposed by catalytic cracking reactions with a heated tungsten catalyzer placed near substrates, and SiNx films are formed at substrate temperatures around 300°C without using plasma. In the paper, additionally the effect of post-deposited treatments by using NH3-decomposed species or hydrogen (H2)-decomposed species formed by catalytic cracking of NH3 and H2 are also studied. It is found that a small hysteresis loop is seen in the C-V curve of as-deposited Cat-CVD SiNx films and that the leakage currents with thickness of 3nm equivalent oxide thickness (EOT) is slightly larger than that in the conventional thermal SiO2 of similar EOT. However, it is also found that the properties of Cat-CVD SiNx films are drastically improved by the post-deposited H2 or NH3 treatments, that is, the hysteresis loop disappears and the leakage current decreases by three orders of magnitude.

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This paper reports a procedure for low-temperature oxidation of silicon surfaces using activated species produced by catalytic decomposition of a gas mixture of H2 and O2 on heated tungsten in a catalytic chemical vapor deposition system. The surface of Si(100) was oxidized at temperatures as low as 200 °C. Silicon oxide layers are obtained with a maximum thickness of 4.2 nm. X-ray photoelectron spectroscopy measurements revealed that the density of intermediate oxidation states is comparable with the thermally oxidized sample whose value is as low as 7×1014 cm-2.

DOI： 10.1149/1.1390846

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Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)

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Polycrystalline silicon (poly-Si) films are obtained at temperatures lower than 400 °C by catalytic chemical vapor deposition (Catalytic CVD = Cat-CVD) method, often called hot-wire CVD method. Structural properties of the Cat-CVD poly-Si films, deposited with various gas pressures, are studied by Raman scattering spectroscopy and X-ray diffraction technique. It is found that there are two recipes for obtaining device quality poly-Si films, that is, such poly-Si films are obtained at low gas pressure around 1 mTorr or less as already reported, and also at high gas pressure around 0.1 to 1 Torr. It is also found that, in addition to catalyzer temperature, the gas pressure is a key factors to obtain device quality poly-Si films at high deposition rates.

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We propose a novel preparation of high quality silicon nitride (SiNx) films by catalytic chemical vapor deposition (Cat-CVD) method for the application of antireflection coatings. It is found that the refractive index (n) of the Cat-CVD SiNx films are controlled from 2.0 to 2.5 by varying the flow ratio of SiH4 and NH3. The properties of the SiNx (n = 2.0) are investigated, and it is found that, 1) the 16-BHF etching rate of the Cat-CVD SiNx film is only 23 A/min, and the film shows excellent moisture resistance, 2) the Cat-CVD SiNx film shows good insulating properties, and the breakdown electric field is higher than 9 MV/cm and the interface state density is 5.6 × 1011 cm-2eV-1, 3) the step coverage of the film is very conformal.

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DOI： 10.1143/JJAP.37.295

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This letter reports a procedure for low-temperature nitridation of silicon surfaces using species produced by NH3catalytic decomposition on heated tungsten in a catalytic chemical vapor deposition system. The surface of Si(100) was nitrided at temperatures as low as 200 °C. Silicon oxinitride films are obtained with a stoichiometry Si:N:O=1:0.9:0.3, a maximum thickness as high as 4.8 nm and an electrical breakdown field of 6 MV/cm. © 1997 American Institute of Physics.

DOI： 10.1063/1.119897

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Language：English   Publishing type：Research paper (scientific journal)

Language：Japanese   Publishing type：Research paper (scientific journal)

Language：Japanese   Publishing type：Research paper (scientific journal)

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)

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Polycrystalline silicon (poly-Si) films are deposited at temperatures lower than 300-400°C by the cat-CVD method. In the method, a SiH4 and H2 gas-mixture is decomposed by catalytic cracking reactions with a heated tungsten catalyzer placed near substrates. Carrier transport, optical and structural properties are investigated for this cat-CVD poly-Si. The films show both large carrier mobility and large optical absorption for particular deposition conditions. The cat-CVD poly-Si films are found to be one of the useful materials for thin film transistors and thin film solar cells.

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DOI： 10.1016/S0169-4332(96)00180-8

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The valence band offsets at the heterointerfaces of the CdF2/CaF2/Si(111) structure grown by molecular beam epitaxy were evaluated using x-ray photoelectron spectroscopy, and the energy band diagram of this heterostructure was proposed. It was found that the interface of CdF2/CaF2has large conduction band offset: 2.9 eV, and the energy level of CdF2conduction band edge is below that of Si.© 1995 American Institute of Physics.

DOI： 10.1063/1.114595

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Epitaxial CdF2 layers and CdF2CaF2 superlattices have been grown on Si(111) substrates by means of molecular beam epitaxy. Double crystal X-ray diffractometry showed their high structural perfection. X-ray photoelectron spectroscopy revealed that CdF2 conduction band lies below that of Si by 0.8 eV. It was found from the cathodoluminescence measurements that Eu3+ ions in epitaxial layer occupy C4v sites. © 1995.

DOI： 10.1016/0167-9317(95)00046-B

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Language：English   Publishing type：Research paper (other academic)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

Language：English   Publishing type：Research paper (scientific journal)

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Epitaxial CdF2 was grown on the coherent or relaxed CaF2/Si(111) by molecular beam epitaxy. The structures were characterized by reflection high-energy electron diffraction, Rutherford backscattering spectroscopy and double-crystal X-ray diffraction. It was shown that the crystallinity of the CdF2 layer grown on the CaF2/Si(111) structure, where the CaF2 was coherently grown on the Si, was quite good so as to obtain 51 arc sec of full width at half maximum of X-ray diffraction. © 1995, All rights reserved.

DOI： 10.1016/0022-0248(95)80112-P

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Surface modification of CaF2/Si(111) was studied for the purpose of 1 ML adsorption of group-V atoms on a fluoride surface which is applicable to heteroepitaxy of III-V compound semiconductors on CaF2. By using Rutherford backscattering (RBS) and X-ray photoelectron spectroscopy (XPS), it was found that 1 ML of As and P were successfully adsorbed on a CaF2 surface, and that a 1 ML self-limiting adsorption of As for the electron beam exposure was realized. Also, we propose a model for the adsorption conditions depending on the substrate temperature during surface modification. © 1994.

DOI： 10.1016/0169-4332(94)90268-2

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Cadmium fluoride single crystal layers have been grown on CaF 2/Si(111) or Si(111) substrates by molecular beam epitaxy. The structures are expected to have attractive electronic properties. The growth was monitored by reflections high energy electron diffraction (RHEED) techniques. A distinct (3×3) R30°superstructure has been observed on the CdF 2(111) surface at growth temperatures below 150°C. RHEED intensity oscillations indicate a two-dimensional growth mode of CdF 2.

DOI： 10.1063/1.111395

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Surface modifications of epitaxial CaF2 on Si(111) by low-energy electron beam, in order to get modified surfaces with reduced damage on which high quality GaAs films could be grown, were studied. By using x-ray photoelectron spectroscopy measurements, it was found that it is possible to modify the surface of CaF2(111) even though the energy of the electron beam was as low as ∼10 eV. The generation of defects in bulk CaF2 and the diffusion of As were found at an energy of 305 eV, whereas no such evidence of defect, but rather, a stable adsorption of As on the surface of CaF2, was observed at an energy of 40 eV.

DOI： 10.1063/1.356272

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