Curling and Annealing Study of Sputtered Thin Spinel Films Delaminated from Lift-Off Polyimide

1997 ◽  
Vol 505 ◽  
Author(s):  
Rand Dannenberg ◽  
Alexander H. King ◽  
Richard J. Gambino ◽  
Alan J. Doctor

ABSTRACTFilms of Mnl.56Co0.96Ni0.48O4, 6–10 ¼m thick, were RF-magnetron sputtered onto the high temperature lift-off polyimide PiRL®; (made by Brewer Science, Inc.), and patterned into long, narrow beams using photolithography. The beams would self-delaminate, curling towards the substrate upon cooling from 300°C to room temperature after sputtering, as a result of the stress gradient in the film, caused by the deposition process. The typical radius of curvature is 8000 ¼m. Upon annealing at temperatures as low as 250°C for 10 minutes, the delaminated films continue to curl. The films curl to equilibrium radii that are functions of the annealing atmosphere and temperature. Films annealed in H2/N2 or vacuum curl more slowly than in air. TEM reveals that the first 100 nm of film is relatively porous, nanocrystalline spinel which densify instantaneously when exposed to high electron beam currents. Analysis of TEM photographs before and after annealing at 250°C indicate that the level of porosity decreases in the films by 1% which can account for the change in the curl radius. The first layers of film at the PiRL-film interface are prevented from fully densifying while on the substrate. When the film delaminates and the constraint is removed, the initial layer can densify, sintering at low temperature because the large specific surface area of the nano-crystalline microstructure provides high driving forces. The nature of the substrate-induced constraint is not fully understood. Water vapor and other light elements may be released from the polyimide if it were to continue to imidize during the deposition, and a SIMS study has been undertaken to investigate this possibility. Alternatively, the constraint may be purely mechanical, where the sintering rate is reduced as in constrained sintering of films from slurry. This effect may be important to understand when ceramic films are patterned with lift-off techniques. Empirical expressions describing the curl are developed.

Author(s):  
Fengchen Wang ◽  
Yan Chen

This paper presents a novel mass-center-position (MCP) metric for vehicle rollover propensity detection. MCP is first determined by estimating the positions of the center of mass of one sprung mass and two unsprung masses with two switchable roll motion models, before and after tire lift-off. The roll motion information without saturation can then be provided through MCP continuously. Moreover, to detect completed rollover statues for both tripped and untripped rollovers, the criteria are derived from d’Alembert principle and moment balance conditions based on MCP. In addition to tire lift-off, three new rollover statues, rollover threshold, rollover occurrence, and vehicle jumping into air can be all identified by the proposed criteria. Compared with an existing rollover index, lateral load transfer ratio, the fishhook maneuver simulation results in CarSim® for an E-class SUV show that MCP metric can successfully predict the vehicle impending rollover without saturation for untripped rollovers. Tripped rollovers caused by a triangle road bump are also successfully detected in the simulation. Thus, MCP metric can be successfully applied for rollover propensity prediction.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kooliyankal Naseema ◽  
Kaniyamkandy Ribin ◽  
Nidiyanga Navya ◽  
Prasoon Prasannan

AbstractNano crystalline zinc sulfide thin films were deposited onto glass substrates by chemical bath deposition method. One of the samples was annealed at 300 °C for 2 h in air using a muffle furnace. The prepared thin films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and Raman spectroscopy (FT-R) studies before and after annealing. The analysis confirmed the thermal-induced anion substitution and conversion of ZnS crystal to ZnO wurtzite crystal. XRD pattern showed that these films were phase pure and polycrystalline in nature. Optical band gap was found to be 3.86 eV for ZnS and 3.21 eV for ZnO. The films prepared by this simple, low-cost technique are suitable for photovoltaic and optoelectronic applications.


1989 ◽  
Vol 162 ◽  
Author(s):  
Sacharia Albin ◽  
Linwood Watkins

ABSTRACTCurrent-voltage characteristics of type Ia synthetic diamond, type IIb natural diamond and free-standing diamond films were measured before and after hydrogenation. The diamond films were polycrystalline, deposited on sacrificial silicon substrates using a microwave chemical vapor deposition process. On hydrogenation, all the samples showed several orders of magnitude increase in conductivity. Hydrogenation was carried out under controlled conditions to study the changes in the I-V characteristics of the samples. The concentration of electrically active hydrogen was determined from the I-V data. Hydrogen passivation of deep traps in diamond is clearly demonstrated.


2010 ◽  
Vol 447-448 ◽  
pp. 725-729 ◽  
Author(s):  
Jhun Yew Cheong ◽  
Xing Zhao Ding ◽  
Beng Kang Tay ◽  
Xian Ting Zeng

In this paper, CrAlSiN coatings are deposited by a lateral rotating cathode arc technique. The high temperature oxidation behaviors of these coatings are studied in ambient atmosphere at temperatures ranging from 800°C-1000°C for an hour. The ternary TiAlN coating is used as the benchmark in this study. The surface morphology and chemical composition of the coating samples before and after oxidation at different temperatures are analyzed by scanning electron microscopy (SEM) equipped by energy dispersive X-ray spectrometer (EDX), glow discharge optical spectrometry (GDOS) and X-ray diffraction (XRD). The CrAlSiN coatings show much better oxidation resistance than the TiAlN coatings. TiAlN starts to oxidize from 800oC and forms a complete surface oxide layer after oxidation at 1000oC for an hour. However, CrAlSiN shows a relatively good oxidation resistance below 1000oC and only is oxidized to form a thin oxide scale with a thickness of 0.3 µm at 1000oC for one hour. It is found that the oxidation of both coatings is triggered from the surface metallic droplets generated by the arc deposition process.


1999 ◽  
Vol 584 ◽  
Author(s):  
T. Ishii ◽  
H. Nozawa ◽  
E. Kuramochi ◽  
T. Tamamura

AbstractA nanocomposite resist system that incorporates sub-nm fullerene molecules ( C60 and/or C70) into a conventional resist material is proposed for nanolithograpy. Fullerene has physically and chemically resistant characteristics, and its incorporation reinforces the original resist film, leading to substantial improvements in resist performance: etching resistance, pattern contrast, mechanical strength and thermal resistance. We have prepared a system composed of a positive-type electron beam resist, ZEP520, and C60 or a C60/C70 mixture and through the fabrication of high electron mobility transistors (HEMTs), X-ray masks, and groove-grating mirrors for lasers with nanometer dimensions confirmed improved resist performance, particularly resolution improvements due to enhanced etching resistance. By making use of a characteristic unique to the nanocomposite, which is that sensitivity readily changes with the fullerene content due to a dissolution inhibiting effect of fullerene, we have constructed a fullerene-incorporated bilayer resist system for a lift-off process and have successfully fabricated a highly-ordered array of self-organized boxlike nanostructures and a mold for nanoprinting. Further, solubility enhancement by fullerene derivatives has been examined for a higher degree of fullerene incorporation and better sensitivity characteristics in future nanocomposite resist systems.


2015 ◽  
Vol 1088 ◽  
pp. 107-111
Author(s):  
Jian Shuang Liu ◽  
Fang Fang Zhu ◽  
Fei Lu ◽  
Lin Zhang

A plasma enhanced atomic layer deposition process has been demonstrated for Lanthanum oxide films using La (thd)3 precursor and oxygen plasma. The chemical and electrical properties of La2O3 ultra-thin films on Si (100) substrates before and after post-annealing in N2 ambient have been investigated. X-ray photoelectron spectroscopic revealed that interface reactions take place after annealing process which lead to oxygen insufficiency, as well as the balance band offset decreases with the increase of annealing temperature. The capacitance-voltage and current-voltage characteristics show La2O3 capacitors annealed at 900 °C have negligible hysteresis, smaller interface trap density in comparison with as-deposited samples, but larger flat band voltage and higher gate-leakage current density due to the appearance of oxygen vacancy in the La2O3 films.


2006 ◽  
Vol 983 ◽  
Author(s):  
Yuhong Wu ◽  
Meng Qu ◽  
Lucille A Giannuzzi ◽  
Sanjay Sampath ◽  
Andrew Gouldstone

AbstractThermally sprayed (TS) coatings are widely used for surface engineering across a range of industries, including aerospace, infrastructure and biomedical. TS materials are formed via the successive impingement, rapid quenching and build-up of molten powder particles on a substrate. The impacted ‘splats’ are thus the fundamental microstructural constituents of the coatings, and their intrinsic properties, as well as intersplat bonding and morphology, dictate coating behavior. Beyond the obvious practical considerations, from a scientific standpoint, splats represent a fascinating template for study, due to the highly non-equilibrium processing conditions (rapid deceleration from sub-sonic velocities, million-degree/sec cooling rates). In the literature, many studies of isolated splats on substrates have been carried out, but these have focused on overall morphology (disc-shape vs fragmented). Direct observations of microstructure, in particular cross-section, are limited in the specimen preparation stage due to splat size (tens of microns in diameter, 1-2 microns in thickness). However, Focused Ion Beam (FIB) techniques have allowed this problem to be addressed in a robust manner; in this paper we will discuss such approaches to observe Ni5Al splats on stainless steel substrates. Cross-sections through the splat and the substrate were created by recourse to ion milling and the ion beam itself provided good channeling contrast for grain imaging. The typical splat microstructure with sub-micron Ni(Al) columnar grains, a chill zone at the bottom and a lift off area is observed in high detail. In addition, an amorphous aluminum oxide top layer of 100-200 nm is partially present on top of the Ni(Al) columnar grains. At the splat/substrate interface, defects such as micro- and nano-scale pores were characterized for the first time and will be discussed. These observations provide insights into splat and interface formation during the deposition process and may drastically improve our current understanding of Ni5Al splat properties.


2012 ◽  
Vol 523-524 ◽  
pp. 787-792 ◽  
Author(s):  
Eiji Morinaga ◽  
Yutaka Matsuura ◽  
Hidefumi Wakamatsu ◽  
Ryohei Satoh ◽  
Koji Nakagawa ◽  
...  

Thin film patterning by a lift-off method is effective from the viewpoint of cost performance and environmental issues. As a solution to the problems of conventional lift-off methods, the inversely-tapered resist profile with interstice was proposed and its fundamental feasibility was experimenatally proved. The resist profile still needed to be designed properly to solve the problems completely, and therefore a design method was also suggested. The method presupposes that conditions of deposition process have been already determined. However, actually, the conditions relate closely to the design of resist profile and wrong conditions may result in undesirable or infeasible design result. This paper proposes an integrated design method of the thin film patterning process considering design of both resist profile and deposition conditions.


2008 ◽  
Vol 1079 ◽  
Author(s):  
Junichi Koike ◽  
Junichi Koike ◽  
Zsolt Tökei

ABSTRACTSelf-forming barrier process was carried out on a porous low-k material with the Cu-Mn alloys. The effects of various surface treatments were investigated in the sample having a pore size of 0.9 nm and a porosity of 25%. Before and after annealing, samples were analyzed in cross section with transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). Concentration profile was also analyzed with time-of-flight secondary ion mass spectroscopy (ToF-SIMS). The results indicated the penetration of Cu into the low-k interior during deposition, followed by the segregation of Cu at the low-k/Si interface during subsequent annealing. Although a diffusion barrier layer was formed and no further Cu penetration was not observed during annealing, initial Cu penetration in the deposition process was detrimental and should be prevented by restoring the plasma damage on the low-k surface.


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