Solvent-Induced Damage in Polyimide Thin Films

MRS Proceedings ◽

10.1557/proc-167-153 ◽

1989 ◽

Vol 167 ◽

Author(s):

M. S. Hu

Keyword(s):

Thin Films ◽

Film Thickness ◽

Exposure Time ◽

Critical Strain ◽

Threshold Value ◽

Weak Dependence ◽

Polyimide Films ◽

Band Formation ◽

Enhanced Diffusion ◽

Wide Range

AbstractSolvent induced damage bands formed in residually strained polyimide thin films on different substrates have been studied. Microscopy studies have shown that these bands resemble crazes. A mechanics approach Is taken to understand the band formation phenomenon.The critical strain for damage formation has been identified. This strain decreases with increase in exposure time, but always exhibits a threshold value. In contrast to the cracking of brittle films, the critical strain has only a weak dependence on the film thickness over a wide range. This behavior obtains because the crazing of the polyimide films is nucleation controlled. Strain-enhanced diffusion of solvent into the films is considered to be responsible for the property degradation that leads to damage formation.

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Characteristics of SnO2 Thin Films Deposited by RF Magnetron Sputtering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.449-452.993 ◽

2004 ◽

Vol 449-452 ◽

pp. 993-996 ◽

Cited By ~ 1

Author(s):

Hyun Wook Ryu ◽

Yong Joo Park ◽

Hyo Sup Noh ◽

Jin Seong Park

Keyword(s):

Thin Films ◽

Film Thickness ◽

Gas Flow ◽

Rf Magnetron Sputtering ◽

Flow Ratio ◽

Post Annealing ◽

Wide Range ◽

Gas Flow Ratio ◽

Small Grains ◽

Film Characteristics

SnO2 thin films were prepared on SiO2/Si substrate by RF-Magentron Sputtering method, varying the deposition time and Ar-to-O2 flow ratio. The post-annealing was conducted at 500 oC and 700 oC in Ar and O2 atmosphere, respectively. Film characteristics were very sensitive to the gas flow ratio during the deposition and the conditions of post-annealing. The Film thickness decreased with decreasing of Ar flow ratio at a constant amount (50 sccm) of total gas flow. Especially, the film deposited under Ar-O2 mixture gas (Ar-to-O2 ratio of 50%) showed clearly aggregated morphology of small particles (cauliflower) in a wide range of area. In the annealed films, these cauliflowers separated some small grains, decreasing the film thickness.

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Ion Beam Mixing of Ni-Ti Bilayered Thin Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118345 ◽

1985 ◽

Vol 43 ◽

pp. 290-291

Author(s):

A. K. Rai ◽

R. S. Bhattacharya ◽

M. H. Rashid

Keyword(s):

Crystal Structure ◽

Thin Films ◽

Amorphous Alloys ◽

Ion Beam ◽

Ion Bombardment ◽

High Energy ◽

Mixing Efficiency ◽

Ion Beam Mixing ◽

Enhanced Diffusion ◽

Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

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Giant Anisotropy of Conductivity in Hydrogenated Nanocrystalline Silicon Thin Films

MRS Proceedings ◽

10.1557/proc-536-275 ◽

1998 ◽

Vol 536 ◽

Author(s):

A. B. Pevtsov ◽

N. A. Feoktistov ◽

V. G. Golubev

Keyword(s):

Thin Films ◽

Film Thickness ◽

Percolation Theory ◽

Nanocrystalline Silicon ◽

Spatial Light Modulators ◽

Light Emitting ◽

Light Modulators ◽

Silicon Thin Films ◽

Longitudinal Conductivity ◽

Transverse Conductivity

AbstractThin (<1000 Å) hydrogenated nanocrystalline silicon films are widely used in solar cells, light emitting diodes, and spatial light modulators. In this work the conductivity of doped and undoped amorphous-nanocrystalline silicon thin films is studied as a function of film thickness: a giant anisotropy of conductivity is established. The longitudinal conductivity decreases dramatically (by a factor of 109 − 1010) as the layer thickness is reduced from 1500 Å to 200 Å, while the transverse conductivity remains close to that of a doped a- Si:H. The data obtained are interpreted in terms of the percolation theory.

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A Slot-Die Technique for the Preparation of Continuous, High-Area, Chitosan-Based Thin Films

Polymers ◽

10.3390/polym13101566 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1566

Author(s):

Oliver J. Pemble ◽

Maria Bardosova ◽

Ian M. Povey ◽

Martyn E. Pemble

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

High Volume ◽

Mechanical Anisotropy ◽

Diverse Range ◽

Direction Parallel ◽

High Area ◽

Wide Range ◽

Slot Die ◽

Potential Applications

Chitosan-based films have a diverse range of potential applications but are currently limited in terms of commercial use due to a lack of methods specifically designed to produce thin films in high volumes. To address this limitation directly, hydrogels prepared from chitosan, chitosan-tetraethoxy silane, also known as tetraethyl orthosilicate (TEOS) and chitosan-glutaraldehyde have been used to prepare continuous thin films using a slot-die technique which is described in detail. By way of preliminary analysis of the resulting films for comparison purposes with films made by other methods, the mechanical strength of the films produced was assessed. It was found that as expected, the hybrid films made with TEOS and glutaraldehyde both show a higher yield strength than the films made with chitosan alone. In all cases, the mechanical properties of the films were found to compare very favorably with similar measurements reported in the literature. In order to assess the possible influence of the direction in which the hydrogel passes through the slot-die on the mechanical properties of the films, testing was performed on plain chitosan samples cut in a direction parallel to the direction of travel and perpendicular to this direction. It was found that there was no evidence of any mechanical anisotropy induced by the slot die process. The examples presented here serve to illustrate how the slot-die approach may be used to create high-volume, high-area chitosan-based films cheaply and rapidly. It is suggested that an approach of the type described here may facilitate the use of chitosan-based films for a wide range of important applications.

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Optical Constant and Conformality Analysis of SiO2 Thin Films Deposited on Linear Array Microstructure Substrate by PECVD

Coatings ◽

10.3390/coatings11050510 ◽

2021 ◽

Vol 11 (5) ◽

pp. 510

Author(s):

Yongqiang Pan ◽

Huan Liu ◽

Zhuoman Wang ◽

Jinmei Jia ◽

Jijie Zhao

Keyword(s):

Thin Films ◽

Film Thickness ◽

Deposition Rate ◽

Optical Constant ◽

Photoelectron Spectroscopy ◽

Linear Array ◽

Chemical Vapor ◽

Rf Plasma ◽

X Ray ◽

Sio2 Thin Film

SiO2 thin films are deposited by radio frequency (RF) plasma-enhanced chemical vapor deposition (PECVD) technique using SiH4 and N2O as precursor gases. The stoichiometry of SiO2 thin films is determined by the X-ray photoelectron spectroscopy (XPS), and the optical constant n and k are obtained by using variable angle spectroscopic ellipsometer (VASE) in the spectral range 380–1600 nm. The refractive index and extinction coefficient of the deposited SiO2 thin films at 500 nm are 1.464 and 0.0069, respectively. The deposition rate of SiO2 thin films is controlled by changing the reaction pressure. The effects of deposition rate, film thickness, and microstructure size on the conformality of SiO2 thin films are studied. The conformality of SiO2 thin films increases from 0.68 to 0.91, with the increase of deposition rate of the SiO2 thin film from 20.84 to 41.92 nm/min. The conformality of SiO2 thin films decreases with the increase of film thickness, and the higher the step height, the smaller the conformality of SiO2 thin films.

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Emergence and Evolution of Crystallization in TiO2 Thin Films: A Structural and Morphological Study

Nanomaterials ◽

10.3390/nano11061409 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1409

Author(s):

Ofelia Durante ◽

Cinzia Di Giorgio ◽

Veronica Granata ◽

Joshua Neilson ◽

Rosalba Fittipaldi ◽

...

Keyword(s):

Thin Films ◽

Film Thickness ◽

Transition Metal Oxides ◽

Annealing Temperature ◽

Morphological Properties ◽

Degree Of Crystallinity ◽

Tio2 Thin Films ◽

Force Microscopy ◽

Heat Treated ◽

Complementary Techniques

Among all transition metal oxides, titanium dioxide (TiO2) is one of the most intensively investigated materials due to its large range of applications, both in the amorphous and crystalline forms. We have produced amorphous TiO2 thin films by means of room temperature ion-plasma assisted e-beam deposition, and we have heat-treated the samples to study the onset of crystallization. Herein, we have detailed the earliest stage and the evolution of crystallization, as a function of both the annealing temperature, in the range 250–1000 °C, and the TiO2 thickness, varying between 5 and 200 nm. We have explored the structural and morphological properties of the as grown and heat-treated samples with Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Diffractometry, and Raman spectroscopy. We have observed an increasing crystallization onset temperature as the film thickness is reduced, as well as remarkable differences in the crystallization evolution, depending on the film thickness. Moreover, we have shown a strong cross-talking among the complementary techniques used displaying that also surface imaging can provide distinctive information on material crystallization. Finally, we have also explored the phonon lifetime as a function of the TiO2 thickness and annealing temperature, both ultimately affecting the degree of crystallinity.

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Experimental Study on the Thickness-Dependent Hardness of SiO2 Thin Films Using Nanoindentation

Coatings ◽

10.3390/coatings11010023 ◽

2020 ◽

Vol 11 (1) ◽

pp. 23

Author(s):

Weiguang Zhang ◽

Jijun Li ◽

Yongming Xing ◽

Xiaomeng Nie ◽

Fengchao Lang ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Grain Size ◽

Integrated Circuits ◽

Film Thickness ◽

Depth Range ◽

Micro Electro Mechanical Systems ◽

Si Substrates ◽

Sio2 Thin Film ◽

Average Grain Size

SiO2 thin films are widely used in micro-electro-mechanical systems, integrated circuits and optical thin film devices. Tremendous efforts have been devoted to studying the preparation technology and optical properties of SiO2 thin films, but little attention has been paid to their mechanical properties. Herein, the surface morphology of the 500-nm-thick, 1000-nm-thick and 2000-nm-thick SiO2 thin films on the Si substrates was observed by atomic force microscopy. The hardnesses of the three SiO2 thin films with different thicknesses were investigated by nanoindentation technique, and the dependence of the hardness of the SiO2 thin film with its thickness was analyzed. The results showed that the average grain size of SiO2 thin film increased with increasing film thickness. For the three SiO2 thin films with different thicknesses, the same relative penetration depth range of ~0.4–0.5 existed, above which the intrinsic hardness without substrate influence can be determined. The average intrinsic hardness of the SiO2 thin film decreased with the increasing film thickness and average grain size, which showed the similar trend with the Hall-Petch type relationship.

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Precise control of Jeff=12 magnetic properties in Sr2IrO4 epitaxial thin films by variation of strain and thin film thickness

Physical Review B ◽

10.1103/physrevb.102.214402 ◽

2020 ◽

Vol 102 (21) ◽

Author(s):

Stephan Geprägs ◽

Björn Erik Skovdal ◽

Monika Scheufele ◽

Matthias Opel ◽

Didier Wermeille ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Magnetic Properties ◽

Film Thickness ◽

Epitaxial Thin Films ◽

Thin Film Thickness ◽

Precise Control

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The Growth of Semiconductor Thin Films Studied by RHEED

Australian Journal of Physics ◽

10.1071/ph900583 ◽

1990 ◽

Vol 43 (5) ◽

pp. 583

Author(s):

GL Price

Keyword(s):

Thin Films ◽

Surface Science ◽

High Vacuum ◽

High Energy ◽

Ultra High Vacuum ◽

Large Area ◽

Growth Modes ◽

Semiconductor Thin Films ◽

Wide Range ◽

Recent Developments

Recent developments in the growth of semiconductor thin films are reviewed. The emphasis is on growth by molecular beam epitaxy (MBE). Results obtained by reflection high energy electron diffraction (RHEED) are employed to describe the different kinds of growth processes and the types of materials which can be constructed. MBE is routinely capable of heterostructure growth to atomic precision with a wide range of materials including III-V, IV, II-VI semiconductors, metals, ceramics such as high Tc materials and organics. As the growth proceeds in ultra high vacuum, MBE can take advantage of surface science techniques such as Auger, RHEED and SIMS. RHEED is the essential in-situ probe since the final crystal quality is strongly dependent on the surface reconstruction during growth. RHEED can also be used to calibrate the growth rate, monitor growth kinetics, and distinguish between various growth modes. A major new area is lattice mismatched growth where attempts are being made to construct heterostructures between materials of different lattice constants such as GaAs on Si. Also described are the new techniques of migration enhanced epitaxy and tilted superlattice growth. Finally some comments are given On the means of preparing large area, thin samples for analysis by other techniques from MBE grown films using capping, etching and liftoff.

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