Showing papers on "Atomic layer deposition published in 1994"
Book•
01 May 1994
TL;DR: In this paper, the authors present thin film technology, thin film characterisation, and high energy techniques for thin film. But they do not discuss the effects of these technologies on the performance of the film.
Abstract: Thin Film Technology. Gas Kinetics. Vacuum Technology. Evaporation. Deposition. Epitaxy. Chemical Vapor Deposition. High-Energy Techniques. Plasma Processes. Film Characterization.
736 citations
Book•
01 Jan 1994
TL;DR: In this paper, the authors present an overview of the role of plasma-assisted and plasma-enhanced chemical vapor deposition processes in the development of thin films and coatings, as well as their application in a variety of applications.
Abstract: Deposition Technologies: An Overview * Plasmas in Deposition Processes * Surface Preparation For Film and Coating Deposition Processes * Evaporation: Processes, Bulk Microstructures And Mechanical Processes * Sputter Deposition Processes * Ion Plating * Chemical Vapor Deposition * Plasma-Enhanced Chemical Vapor Deposition * Plasma-Assisted Vapor Deposition Processes: Overview * Deposition from Aqueous Solutions: An Overview * Advanced Thermal Spray Deposition Techniques * Non-Elemental Characterization of Films and Coatings * Film Growth and Structure of PVD Deposits * Metallurgical Applications * Characterization of Thin Films And Coatings.
639 citations
198 citations
TL;DR: Atomic layer epitaxy (ALE) is emerging as a promising epitaxial growth technique for thickness control at the atomic level as discussed by the authors, and recent progress in ALE of III-V and Si thin films.
Abstract: Atomic layer epitaxy (ALE) is emerging as a promising epitaxial growth technique for thickness control at the atomic level. The article outlines recent progress in ALE of III–V and Si thin films. Also models describing the self‐limiting processes will be outlined.
101 citations
TL;DR: In this paper, the growth rate of films varies from 20 to 90 pm/cycle depending on materials and temperature, and the crystallinity, orientation, stoichiometry, atomic density, optical and electrical properties together with growth properties of the films have been characterized.
Abstract: CaF 2 , SrF 2 , and ZnF 2 thin films have been deposited on glass substrates for the first time using atomic layer deposition (ALD) at temperatures between 260 and 400 o C. The source materials used are alkaline earth β-diketonates, zinc acetate dihydrate, and hydrogen fluoride in nitrogen atmosphere. The growth rate of films varies from 20 to 90 pm/cycle depending on materials and temperature. The crystallinity, orientation, stoichiometry, atomic density, optical and electrical properties together with growth properties of the films have been characterized. Also, multilayer structures with alternating materials of high (ZnS) and low (fluoride) index of refraction have been prepared by ALD
61 citations
TL;DR: In this article, the authors optimized the synthesis of zirconium tetramethylheptanedione [Zr(thd)4] using metal-organic chemical vapor deposition (MOCVD).
Abstract: Synthesis of zirconium tetramethylheptanedione [Zr(thd)4] was optimized. Purity of Zr(thd)4 was confirmed by melting point determination, carbon, and hydrogen elemental analysis and proton nuclear magnetic resonance spectrometer (NMR). By using Zr(thd)4, excellent quality ZrO2 thin films were successfully deposited on single-crystal silicon wafers by metal-organic chemical vapor deposition (MOCVD) at reduced pressures. For substrate temperatures below 530 °C, the film deposition rates were very small (⋚1 nm/min). The film deposition rates were significantly affected by (i) source temperature, (ii) substrate temperature, and (iii) total pressure. As-deposited films are carbon free. Furthermore, only the tetragonal ZrO2 phase was identified in as-deposited films. The tetragonal phase transformed progressively into the monoclinic phase as the films were subjected to a high-temperature post-deposition annealing. The optical properties of the ZrO2 thin films as a function of wavelength, in the range of 200 nm to 2000 nm, were also reported. In addition, a simplified theoretical model which considers only a surface reaction was used to analyze the deposition of ZrO2 films. The model predicated the deposition rates well for various conditions in the hot wall reactor.
30 citations
26 citations
Patent•
08 Feb 1994
TL;DR: In this article, an improved method of depositing films of a gate silicon nitride and an amorphous silicon on a thin film transistor substrate at high deposition rates while maintaining superior film quality is provided.
Abstract: An improved method of depositing films of a gate silicon nitride and an amorphous silicon on a thin film transistor substrate at high deposition rates while maintaining superior film quality is provided. The material near the interface between the amorphous silicon and the nitride are deposited at a low deposition rate which produces superior quality films. The region away from the interface are deposited at a high deposition rate which produces lesser, but still good quality films. By using this method, superior quality thin film transistors can be produced at very high efficiency. The method can be carried out by depositing a high quality g-SiN x at a low deposition rate on top of an average quality gate nitride deposited at a high deposition rate and then depositing an amorphous silicon layer. It also applies in a process where high quality amorphous silicon is first deposited at a low deposition rate on a gate nitride layer to form an interface, and then average quality amorphous silicon is deposited at a high deposition rate to complete the silicon layer. The unique process can be applied whenever an interface exists with an active semiconductor layer of amorphous silicon. The process is applicable to either the back channel etched TFT device or the etch stopped TFT device.
23 citations
01 Feb 1994
TL;DR: In this paper, the authors presented results on the ultra-high vacuum chemical vapour deposition of silicon thin films and on the gate-oxide deposition at low temperature by distributed electron-cyclotron-resonance-plasma-enhanced chemical vaporization, showing that high electron mobilities and low off currents characterise the transistors fabricated with these techniques.
Abstract: Polycrystalline silicon is a promising candidate for the fabrication of thin-film transistors used to control the pixel voltage of active-matrix liquid-crystal displays Results are presented on the ultra-high vacuum chemical vapour deposition of silicon thin films and on the gate-oxide deposition at low temperature by distributed electron-cyclotron-resonance-plasma-enhanced chemical vapour deposition It is shown that high electron mobilities and low off currents characterise the transistors fabricated with these techniques
9 citations
05 Dec 1994
TL;DR: In this article, an atom beam sputtered transparent conductive window layer/chemical bath deposited CdS buffer layer/p-type InP single crystal structure was studied and a total area cell efficiency up to 17.8% was obtained at AM 1.5 and was expected to reach as high as 23%.
Abstract: Heterojunction solar cells consisting of an atom beam sputtered transparent conductive window layer/chemical bath deposited CdS buffer layer/p-type InP single crystal structure were studied. A total area cell efficiency up to 17.8% was obtained at AM 1.5 and was expected to reach as high as 23% based on this structure. The buffer layer 45 to 240 nm thick plays a key role to reduce sputter damages which would be formed at the surface of InP without this layer. It was found that the the choice of window materials has an important effect on the aging properties of the cell. When ZnO is used as a window material, the fill factor of the cell was particularly degraded by aging. Using an atom beam sputtered In/sub 2/O/sub 3/ window layer, the authors have been able to obtain more reliable solar cells.
7 citations
05 Dec 1994
TL;DR: In this article, atomic force microscopy (AFM) was used to determine the micro and nanostructures of polycrystalline CdTe thin films used in photovoltaic (PV) cell fabrication.
Abstract: This paper provides first-time correlations of the nanoscale physical structure with the macroscale electronic and optical properties of CdTe/CdS thin films for several standard deposition techniques. Atomic force microscopy (AFM) was used to determine the micro and nanostructures of polycrystalline CdTe thin films used in photovoltaic (PV) cell fabrication. Photoluminescence (PL) was used to determine band gap, relative defect density, and photoexcited carrier lifetime. Nanostructural features (nanograins), beyond the spatial resolution of conventional scanning electron microscopy (SEM), were observed and characterized in as-deposited CdTe. The correlations of the proximal probe measurements of the physical structure with the optically determined electronic properties were used to show the effects of the chemical and heat processing, directly and conclusively. A particularly striking effect with important implications for PV applications is the diffusion of sulfur across the CdTe/CdS interface during heat treatment.
05 Dec 1994
TL;DR: In this paper, the authors proposed a thermal dry surface oxide passivation with hydrogen plasma treatment from the front and the back sides, achieving an efficiency of 17% on 4 cm/sup 2/ (independently confirmed by NREL as 16.93%) without any Al gettering.
Abstract: Conventional (CC) and electromagnetically cast (EMC) multicrystalline silicon solar cells are fabricated following different passivation schemes. Thin layers (/spl sim/100 /spl Aring/) of thermal dry and PECVD SiO/sub 2/ are implemented for providing oxide surface passivation for multicrystalline silicon solar cells. It is found that growing thin layers of thermal dry oxide results in efficient surface passivation. However, for thin PECVD SiO/sub 2/ layers it is necessary to perform, post deposition, low temperature (/spl sim/350/spl deg/C) forming gas anneal in order to observe the surface passivation effect. In addition, hydrogen plasma passivation has been optimized for achieving very deep penetration of atomic hydrogen in the material (>30 /spl mu/m) and as a consequence very effective bulk passivation of multicrystalline silicon solar cells. By combining the thermal dry surface oxide passivation with the hydrogen plasma treatment from the front and the back sides, efficiency of 17% on 4 cm/sup 2/ (independently confirmed by NREL as 16.93%) is realized without any Al gettering. On the other hand, the solar cell efficiencies obtained using thin layers of PECVD SiO/sub 2/ are found to be very comparable to the efficiency of the cells fabricated with thermal dry SiO/sub 2/ layers.
01 Jan 1994
TL;DR: In this paper, the authors used a distributed electron-cyclotron-resonance-plasma-enhanced chemical vapour deposition (ECVED) for the fabrication of thin-film transistors for active-matrix liquid-crystal displays.
Abstract: Polycrystalline silicon is a promising candidate for the fabrication of thin-film transistors used to control the pixel voltage of active-matrix liquid-crystal displays. Results are presented on the ultra-high vacuum chemical vapour deposition of silicon thin films and on the gate-oxide deposition at low temperature by distributed electron-cyclotron-resonance-plasma-enhanced chemical vapour deposition. It is shown that high electron mobilities and low off currents characterise the transistors fabricated with these techniques
05 Dec 1994
TL;DR: In this article, the role of atomic hydrogens in chemical annealing is revealed, where the deposition of thin layer and treatment with atomic hydrogen are repeated alternately for fabrication of a stable structure.
Abstract: A systematic study has been performed to reveal the role of atomic hydrogens in "chemical annealing", where the deposition of thin layer and treatment with atomic hydrogen are repeated alternately for fabrication of a stable structure. Relaxation resulting from impingement of atomic hydrogen on the growing surface are distinguished into two pieces, viz., relaxation on the surface and the sub-surface depending on the conditions for deposition of thin layer and the flux of atomic hydrogen. The structural changes within the sub-surface resulted in either formation of wider gap films or crystallization at rather low substrate temperature (Ts:100-150 C). At high Ts, on the other hand, the structural relaxations are mainly promoted on the growing surface, resulting in formation of the narrower optical gap a-Si:H and stimulating the grain growth.
05 Dec 1994
TL;DR: The main role of atomic hydrogen on crystallization is promotion of "grain growth" within the sub-surface of several nanometers thick beneath the growing surface in the case of growing poly-Si from fluorinated precursors.
Abstract: Polysilicon thin films, exhibiting both high crystallinity (100 vo1%) and photoconductivity, were successfully fabricated on glass substrates at 360/spl deg/C from fluorinated precursors SiFnHm (n+m/spl les/3) Furthermore, crystallinity around the interface region between glass and film was effectively improved by the layer-by-layer (LBL) technique wherein deposition of thin layer (/spl sim/4 nm) and exposure to atomic hydrogen were alternately repeated It is clarified by in situ real time spectroscopic ellipsometry that the main role of atomic hydrogen on crystallization is promotion of "grain growth" within the sub-surface of several nanometers thick beneath the growing surface in the case of growing poly-Si from fluorinated precursors
TL;DR: In this article, a diamond thin film on non-diamond substrates at low pressures (100 kΩ-cm) was constructed by hot filament chemical vapour deposition technique.
Abstract: Deposition of diamond thin films on non-diamond substrates at low pressures ( 100 kΩ-cm) 〈100〉 oriented silicon substrates by hot filament chemical vapour deposition technique are described in this review paper.
TL;DR: In this article, the deposition chemistry and bonding of the hydrogenated amorphous materials a-C:H, a-Si:H and a-Ge:H are discussed.
TL;DR: In this article, a new chemical vapor deposition (CVD) reactor is presented for both epitaxial and none-pitaxial film deposition in semiconductor processing, where the supply of the source gas for the deposition is by diffusion through a porous material such as quartz or graphite.
Abstract: The concept and design of a new chemical vapor deposition (CVD) reactor is presented for both epitaxial and nonepitaxial film deposition in semiconductor processing. The reactor is designed in such a way that a stagnant semiconductor source fluid of uniform concentration is provided for the film deposition without causing free or forced convection. The supply of the source gas for the deposition is by diffusion through a porous material such as quartz or graphite. Compared to the low pressure CVD (LPCVD) reactor with mounted wafer configuration, the new reactor should give a better film thickness uniformity and about an order of magnitude reduction in the amount of the source gas required. Further, at least for polycrystalline silicon deposition, the deposition rate can be much higher than is currently practiced with the LPCVD reactor. Design equations for the reactor are given. Details on the design for the polycrystalline silicon deposition are also given.
TL;DR: In this article, Co/Cu multilayer films were deposited on glass substrate by both vacuum evaporation and sputtering methods, and the surface morphology and resistivity were investigated in order to determine the influence of the preparation methods on the film structure.
Abstract: Co/Cu multilayer films were deposited on glass substrate by both vacuum evaporation and sputtering methods. Pure Cu films were also prepared by the same methods. The surface morphology and resistivity were investigated in order to determine the influence of the preparation methods on the film structure. The MR ratio oscillates with the Cu layer thickness d Cu in sputtered multilayer films prepared at low Ar pressure (15 mTorr), whereas it increases monotonically with d Cu in sputtered multilayer films prepared at high Ar pressure (50 mTorr). On the other hand, the MR ratio oscillates with d Cu only beyond 20A in evaporation-deposited multilayer films prepared at a high deposition rate (2A/s). The MR ratio of the samples perpared at a low deposition rate (0.5A/s) is nearly zero. AFM observations of the multilayer and Cu films indicated the existence of a rumpling of the layered structure, with a fluctuation period of 100 to 500A. The fluctuation of the rumpling is large in multilayer films evaporation-deposited at a low rate (0.5A/s) and small in multilayer films sputter-deposited at low pressure (15 mTorr). The difference in the MR ratios of samples prepared by the two methods and under different conditions is mainly due to the differences in multilayer stacking structures.
Proceedings Article•
01 Sep 1994TL;DR: In this paper, a method for obtaining thin oxynitride insulator is described: a nitrogen doped silicon layer is used as a nitrogen atoms source for the nitridation of a buried oxide layer.
Abstract: A new method for the obtaining of thin oxynitride insulator is described: a nitrogen doped silicon layer is used as a nitrogen atoms source for the nitridation of a buried oxide layer. Capacitor structures are made and electrical characterization by C(V) and I(V) of the oxynitride films are presented and analysed.
06 Jun 1994
12 Jul 1994
TL;DR: In this article, the radiation effect on gate oxides prepared by various sequences is studied and it was experimentally observed that all the fluorinated oxides are more radiation hard than the rapid thermal oxide (control oxide).
Abstract: Liquid phase deposition (LPD) following rapid thermal oxidation (RTO) is proposed as a method to obtain the fluorinated gate oxides. The radiation effect on these fluorinated oxides prepared by various sequences is studied. It was experimentally observed that all the fluorinated gate oxides are more radiation hard than the rapid thermal oxide (control oxide). Interestingly, the amount of fluorine (F) incorporated in the gate oxides can be easily and precisely controlled by changing the sequences and the times of LPD process and/or RTO treatment.
01 Jan 1994
TL;DR: In this article, ZnSe has been employed as a buffer layer together with a new fabrication method which has been named as an atomic layer deposition (ALD) method in order to deposit znSe continuously on polycrystalline ClGS thin-film absorber in the form of atomic layer epitaxy (ALE) method.
Abstract: From the standpoint of environmental safety, the establishment of the process to fabricate Cd-free buffer layers is significantly desirable. In this study, ZnSe has been employed as a buffer layer together with a new fabrication method which has been named as an atomic layer deposition (ALD) method in order to deposit ZnSe continuously on polycrystalline ClGS thin-film absorber in the form of an atomic layer epitaxy (ALE) method. The currently best efficiency of polycrystalline ClGS thin-film solar cells with ZnSe buffer layer by the ALD method is
TL;DR: In situ measurements of the longitudinal Kerr effect were used in conjunction with ellipsometry measurements over the photon energy range from 2.0 to 4.6 eV to investigate the magneto-optic properties of polycrystalline Co films deposited on fused quartz substrates as mentioned in this paper.
Abstract: In situ measurements of the longitudinal Kerr effect were used in conjunction with ellipsometry measurements over the photon energy range from 2.0 to 4.6 eV to investigate the magneto-optic properties of polycrystalline Co films deposited on fused quartz substrates. AFM observations and ellipsometry measurements show that Co forms islands on the substrate in the early stages of deposition, and that the films become continuous in an optical sense when their thickness is about 60A. The spectral shapes of both the real and imaginary parts of ?? xy show significant changes for 100A thick films and for films less than 60A thick. The dependence of the spectral shape on the Co coverage is discussed in relation to the film structure. Below 30A, the calculated ?? xy based on formulae for the effective dielectric tensor of a composite material containing fine magnetic particles, and using the measured permittivity of a 100A thick Co film, agrees well with the experimental results.
29 Aug 1994
05 Dec 1994
TL;DR: In this article, ZnSe has been employed as a buffer layer together with a new fabrication method which has been named as an atomic layer deposition (ALD) method in order to deposit znSe continuously on a polycrystalline CIGS thin-film absorber.
Abstract: From the standpoint of environmental safety, the establishment of the process to fabricate Cd-free buffer layers is significantly desirable. In this study, ZnSe has been employed as a buffer layer together with a new fabrication method which has been named as an atomic layer deposition (ALD) method in order to deposit ZnSe continuously on a polycrystalline CIGS thin-film absorber in the form of an atomic layer epitaxy (ALE) method. The currently best efficiency of polycrystalline CIGS thin-film solar cells with ZnSe buffer layer by the ALD method is 11.6%.
TL;DR: In this article, the growth rate of films varies from 20 to 90 pm/cycle depending on materials and temperature, and the crystallinity, orientation, stoichiometry, atomic density, optical and electrical properties together with growth properties of the films have been characterized.
Abstract: CaF 2 , SrF 2 , and ZnF 2 thin films have been deposited on glass substrates for the first time using atomic layer deposition (ALD) at temperatures between 260 and 400 o C. The source materials used are alkaline earth β-diketonates, zinc acetate dihydrate, and hydrogen fluoride in nitrogen atmosphere. The growth rate of films varies from 20 to 90 pm/cycle depending on materials and temperature. The crystallinity, orientation, stoichiometry, atomic density, optical and electrical properties together with growth properties of the films have been characterized. Also, multilayer structures with alternating materials of high (ZnS) and low (fluoride) index of refraction have been prepared by ALD
06 Jul 1994