scholarly journals Advanced Lithography for Nanofabrication

1996 ◽  
Vol 448 ◽  
Author(s):  
Frank Y.C. Hui ◽  
Gyula Eres
Keyword(s):  
Silicon Dioxide ◽  
Film Growth ◽  
Hydrogen Desorption ◽  
Surface Mobility ◽  
Selective Area ◽  
Clean Environment ◽  
Phase Precursor ◽  
Novel Method ◽  
Wet Chemical ◽  
Pattern Resolution

AbstractA novel method for generating lateral features by patterning the naturally forming surface hydride layer on Si is described. Because of the relatively strong chemical bonding between silicon and hydrogen, the hydride layer acts as a robust passivation layer with essentially zero surface mobility at ordinary temperatures. A focused electron beam from a scanning electron microscope was used for patterning. Upon losing the hydrogen passivation the silicon surface sites become highly reactive. Ideally, the lifetime of such a pattern in a clean environment should be infinite. Deliberate exposure of the entire wafer to a suitable gas phase precursor results in selective area film growth on the depassivated pattern. Linewidths and feature sizes of silicon dioxide on silicon below 100 nm were achieved upon exposure to air. The silicon dioxide is robust and allows effective pattern transfer by anisotropic wet-chemical etching. In this paper, the mechanism of hydrogen desorption and subsequent pattern formation, and the factors that govern the ultimate pattern resolution will be discussed.

Synthesis of Photodefinable RuO2 Precursors For Electrode Contacts

1997 ◽  
Vol 493 ◽  
Author(s):  
K. J. Law ◽  
Y. H. Spooner
Keyword(s):  
Chemical Process ◽  
Ruthenium Complexes ◽  
Ferroelectric Thin Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ruthenium Compounds ◽  
Straight Line ◽  
Wet Chemical ◽  
Pattern Forming ◽  
Pattern Resolution

ABSTRACTA wet-chemical process for depositing and patterning RuO2 contacts for use in ferroelectric thin film capacitive devices is described. Three new ruthenium compounds containing photocrosslinkable organic groups have been synthesized which polymerize upon UV exposure. Preliminary pattern forming ability of the new precursors has been tested with the use of a simple straight line contact mask. The exposed portions of the precursor films are resistant to ethanol, acetone, and light abrasion. The formation of crystalline RuO2 upon organic pyrolysis was confirmed by x-ray diffraction. Synthesized ruthenium complexes were compared to commercially available ruthenium acetylacetonate. The synthesized organo-ruthenium complexes showed improvement in pattern resolution and clarity.

Properties of SiO2 Films Fabricated by Microwave Ecr Plasma Processing with and Without Energetic Particle Bombardment During Film Deposition Part I. Fabrication Processes and Physical Properties

1991 ◽  
Vol 223 ◽  
Author(s):  
T. T. Chau ◽  
S. R. Mejia ◽  
K. C. Kao
Keyword(s):  
Silicon Dioxide ◽  
Particle Bombardment ◽  
Energetic Particle ◽  
Deposition Temperature ◽  
Film Growth ◽  
Plasma Processing ◽  
Film Deposition ◽  
Ecr Plasma ◽  
Group A ◽  
Group B

ABSTRACTSilicon dioxide (SiO2) films were fabricated by microwave ECR plasma processing. Two groups of films were fabricated; group A with the substrates placed in a position directly facing the plasma so that the substrates as well as the on-growing films were subjected to bombardment of energetic particles produced in the plasma, and group B with the substrates placed in a processing chamber physically separated from the plasma chamber in order to prevent or suppress the damaging effects resulting from these energetic particle bombardment. The systems used for fabricating these two different groups of samples are described. The films were deposited at various deposition temperatures. On the basis of the deposition rate as a function of deposition temperature the film growth for group A samples is due mainly to mass-limited reaction, and that for group B samples is due to surface rate limited reaction. The stoichiometric level for group A does not change with deposition temperature though the films density increases with increasing deposition temperature. However, group B samples exhibit an off-stoichiometric property but they become highly stoichiometric as the deposition temperature is increased beyond 200 °C

Silicon Surface Preparation and Passivation by Vapor Phase of Heavy Water

2009 ◽  
Vol 145-146 ◽  
pp. 181-184 ◽  
Author(s):  
Andrea E. Pap ◽  
Zsolt Nényei ◽  
Gábor Battistig ◽  
István Bársony
Keyword(s):  
Silicon Surface ◽  
Surface States ◽  
Surface Preparation ◽  
Hydrogen Desorption ◽  
Dangling Bonds ◽  
Hydrogen Atoms ◽  
Surface Band ◽  
Band Bending ◽  
Chemical Treatments ◽  
Wet Chemical

The well known wet chemical treatments of the silicon surface and its native oxidation in air cause a high density of interface states, which predominantly originate from dangling bonds strained bonds or from bonds, between adsorbates and silicon surface atoms. Therefore, a number of wet-chemical treatments have been developed for ultraclean processing in order to produce chemically and electronically passivated surfaces [1]. The saturation of dangling bonds by hydrogen removes the surface states and replaces them by adsorbate-induced states, which influence the surface band-bending [2]. The first thermal hydrogen desorption peak from a hydrogen passivated Si surface in vacuum or inert gas ambient can be detected at around 380°C [3,4]. Simultaneously the combination of the hydrogen atoms of neighboring dihydrides generates a pair of dangling bonds. At around 480-500°C dangling bonds are generated on the silicon surface by desorption of the remaining hydrogen [5]. At that moment the silicon surface becomes extremely reactive.

scholarly journals Development of a Novel Method for the Fabrication of Nanostructured Zr(x)Ni(y) Catalyst to Enhance the Desorption Properties of MgH2

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 849
Author(s):  
Gracia Shokano ◽  
Zahir Dehouche ◽  
Basile Galey ◽  
Georgeta Postole
Keyword(s):  
Hydrogen Desorption ◽  
Milling Process ◽  
Hydrogen Release ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscope Analysis ◽  
Novel Method ◽  
Temperature Programmed ◽  
The Impact

The present work involves the development of a novel method for the fabrication of zirconium nickel (Zr(x)Ni(y)) alloy used as a nanocatalyst to improve the hydrogen storage properties of the Mg/MgH2 system. The catalyst was fabricated through the high-pressure reactor and activated under hydrogen prior to being mechanically milled with the MgH2 for 5 h under argon. The microstructure characterisation of the samples was determined via SEM-EDX (scanning electron microscope analysis–energy dispersive X-ray spectroscopy), XRD (X-ray diffraction) and FE-HRTEM (field emission high resolution transmission electron microscopy), and the desorption characteristic of the nanocomposite (10 wt.% Zr(x)Ni(y)–MgH2) was determined via TPD (temperature-programmed desorption). The nanostructured MgH2 powder milled with 10 wt.% of the activated Zr(x)Ni(y) based nanocatalyst resulted in a faster hydrogen release—5.9 H2-wt.% at onset temperature 210 °C/peak temperature 232 °C. The observed significant improvement in the hydrogen desorption properties was likely to be the result of the impact of the highly dispersed catalyst on the surface of the Mg/MgH2 system, the reduction in particle size during the ball milling process and/or the formation of Mg0.996Zr0.004 phase during the milling process.

Electronic Excitation-Induced Surface Chemistry and Electron-Beam-Assisted Chemical Vapor Deposition

1989 ◽  
Vol 158 ◽  
Author(s):  
F. Bozso ◽  
Ph. Avouris
Keyword(s):  
Electron Beam ◽  
Film Growth ◽  
Molecular Layer ◽  
Chemical Vapor ◽  
Electronic Excitations ◽  
Precise Control ◽  
Selective Area ◽  
Low Energy Electron ◽  
Nitride Oxide ◽  
Molecular Layers

ABSTRACTSelective area deposition of thin films and surface structures with precise control over their composition is possible in UHV by using low energy electron beams to induce electronic excitations in adsorbed molecular layers. Upon electron impact, adsorbed/co-adsorbed molecules decompose into reactive species, resulting in film growth. The composition of the film reflects that of the adsorbed molecular layer, which at cryogenic temperatures can sensitively be controlled by the partial pressure of the reactant gases. We present results of detailed studies of adsorption, thermal and electron-beam-induced dissociation of disilane and ammonia on silicon. We show that by proper choice of temperature, gas phase composition and electron beam, amorphous silicon, silicon nitride, oxide, silicon oxinitride films can be grown with nearly monolayer thickness resolution.

Excellent Surface Passivation by Silicon Dioxide Grown with a Electrochemical Method

2011 ◽  
Vol 685 ◽  
pp. 48-54
Author(s):  
Jun Zhang ◽  
Wei Ming Lu ◽  
Chun Lan Zhou ◽  
Zhen Li Wen ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Silicon Dioxide ◽  
Electrochemical Method ◽  
Silicon Surface ◽  
Surface Passivation ◽  
Comparison Study ◽  
Initial Value ◽  
Effective Lifetime ◽  
Positive Voltage ◽  
Novel Method

A novel method to grow silicon dioxide layers for passivating the silicon surface is given more attention. SiO2was grown by applying a positive voltage across silicon wafers in a nitric acid solution at low temperature. After annealing in N2media at 900°C for 20min, excellent surface passivation was achieved. The maximum effective lifetime of the silicon arrived at 29.8μs and 29.75μs, which was three times the value of silicon without passivation. The effective lifetime of other types of silicon could be ten times the initial value without the silicon dioxide. A comparison study of the effect of the FGA, annealing at low temperature and annealing in N2or O2containing medium at high temperature were investigated.

Predictive Surface Kinetic Analysis: The Case of TiSi2 CVD

1993 ◽  
Vol 334 ◽  
Author(s):  
M. A. Mendicino ◽  
R. P. Southwell ◽  
E. G. Seebauer
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Growth Conditions ◽  
Si Substrate ◽  
Quantitative Correlation ◽  
Selective Area ◽  
Metal Silicides ◽  
High Production ◽  
Reaction Stoichiometry ◽  
Area Deposition

Recently, TiSi2 has been the object of considerable study because of its low resistivity among the transition metal silicides and its compatibility with existing ULSI technology [1,2]. Film growth by CVD offers the potential for selective area deposition and high production throughput. However, selective CVD of TiSi2 from gas phase SiH4 and TiCl4 is usually accompanied by a competing reaction which consumes intolerable amounts of the Si substrate [3,4]. Controlling this consumption is crucial in TiSi2 growth; however, no quantitative correlation exists between silicon consumption and growth conditions or film thickness. Additionally, the reaction mechanism for TiSi2 growth is poorly understood, and some disagreement even exists about the reaction stoichiometry [5,6]. The combined CVD/UHV approach we have developed fills many gaps in the current understanding of TiSi2 CVD.

TEM study of C70 polycrystalline films

1994 ◽  
Vol 9 (11) ◽  
pp. 2814-2822 ◽  
Author(s):  
I. Rusakova ◽  
A. Hamed ◽  
P.H. Hor
Keyword(s):  
Electron Beam ◽  
Structural Changes ◽  
Film Growth ◽  
Lattice Parameter ◽  
Polycrystalline Films ◽  
Surface Mobility ◽  
High Resolution Tem ◽  
Glass Carbon ◽  
Extended Exposure ◽  
Fcc Structure

Using conventional and high resolution TEM, we have studied the microstructure of C70 polycrystalline films, prepared by sublimation of C70 powder onto glass, carbon holey film, and sapphire substrates held at 200 °C. An fcc structure with lattice parameter 1.50 nm is observed for the films on glass and amorphous carbon. A different structure and stronger adherence to the substrate was observed for the thin film grown on sapphire, suggesting a stronger molecule-substrate interaction in this case. Thicker films on sapphire, however, did have fcc structure. In all cases, the film grows in large grains about 100 nm in size, indicating high effective surface mobility of the C70 molecules. Further analysis of the films on carbon holey substrates indicates a preferred [011] film growth orientation, the existence of twins, and a high density of stacking faults. Extended exposure of the films to oxygen did not result in visible structural changes, but strong illumination for several hours in atmosphere led to partial annealing of planar defects and higher sensitivity to the electron beam, with film amorphization taking place at much shorter times under the electron beam.

scholarly journals Site-specific colloidal crystal nucleation by template-enhanced particle transport

2016 ◽  
Vol 113 (43) ◽  
pp. 12094-12098 ◽  
Author(s):  
Chandan K. Mishra ◽  
A. K. Sood ◽  
Rajesh Ganapathy
Keyword(s):  
Self Assembly ◽  
Film Growth ◽  
Colloidal Crystal ◽  
Experimental Studies ◽  
Crystal Nucleation ◽  
Nucleation Density ◽  
Surface Mobility ◽  
Target Sites ◽  
Particle Level ◽  
Spatially Varying

The monomer surface mobility is the single most important parameter that decides the nucleation density and morphology of islands during thin-film growth. During template-assisted surface growth in particular, low surface mobilities can prevent monomers from reaching target sites and this results in a partial to complete loss of nucleation control. Whereas in atomic systems a broad range of surface mobilities can be readily accessed, for colloids, owing to their large size, this window is substantially narrow and therefore imposes severe restrictions in extending template-assisted growth techniques to steer their self-assembly. Here, we circumvented this fundamental limitation by designing templates with spatially varying feature sizes, in this case moiré patterns, which in the presence of short-range depletion attraction presented surface energy gradients for the diffusing colloids. The templates serve a dual purpose: first, directing the particles to target sites by enhancing their surface mean-free paths and second, dictating the size and symmetry of the growing crystallites. Using optical microscopy, we directly followed the nucleation and growth kinetics of colloidal islands on these surfaces at the single-particle level. We demonstrate nucleation control, with high fidelity, in a regime that has remained unaccessed in theoretical, numerical, and experimental studies on atoms and molecules as well. Our findings pave the way for fabricating nontrivial surface architectures composed of complex colloids and nanoparticles as well.

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