Zirconia Thin-Films for Toughened Ceramics

2006 ◽  
Author(s):  
J. Y. Thompson ◽  
B. R. Stoner ◽  
J. R. Piascik
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Film Deposition ◽  
Film Stress ◽  
Grain Structure ◽  
Ambient Conditions ◽  
High Temperature Stability ◽  
Stabilized Zirconia ◽  
Water Vapor Absorption ◽  
Absorption Mechanism

Partially-stabilized zirconia (PSZ) has been studied extensively, due to its high temperature stability and stress-induced tetragonal to monoclinic phase transformation, which can elicit enhanced fracture resistance. Applications include thermal barriers, high-k dielectric gate oxides, biomedical components, and solid oxide fuel cells, where not only temperature is a factor, but aggressive environments can compromise function. Research has advanced from using PSZ in bulk form to creating thin films that utilize the same material properties. PSZ, where the high temperature tetragonal phase is stabilized at room temperature, offers the ability to create a thin film that takes advantage of the unique properties of zirconia by improving the fracture behavior of brittle substrates. Yttria (3 mol%) stabilized zirconia (YSZ) can be deposited by radio frequency (rf) magnetron sputtering under varying deposition parameters to produce thin films with unique microstructures and properties. Most YSZ films are characterized by a columnar grain structure, and it has been found that inter-crystalline porosity and overall film density can be controlled by applying differing substrate bias during film deposition. Film stress can subsequently be manipulated over a broad range. Initial film stresses ranging from approximately 100 MPa tensile to 200 MPa compressive have been reproducibly produced. It has also been found that exposure of YSZ thin films containing measurable inter-granular porosity (10–100Å) to ambient conditions (25°C, 75% relative humidity) leads to a substantial increase in compressive stress of films (as much as 100 MPa). Thermal reversibility of this environmental aging effect suggests a water vapor absorption mechanism that might be tailored to specific applications.

Effect of Oxygen Flow Rate and Post Annealing on Vanadium Oxide Thin Films Prepared by DC Pulse Magnetron Sputtering

2016 ◽  
Vol 675-676 ◽  
pp. 233-236 ◽  
Author(s):  
Wantanee Hincheeranun ◽  
Montri Aiempanakit ◽  
Kamon Aiempanakit ◽  
Mati Horprathum ◽  
Viyapon Patthanasetakul ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Optical Transmission ◽  
Film Surface ◽  
Film Deposition ◽  
Oxygen Flow ◽  
Ambient Conditions ◽  
Flow Rates ◽  
Air Atmosphere ◽  
Post Annealing

In this work, we investigated V2O5 thin films prepared by a DC pulse reactive magnetron sputtering at ambient conditions. The effects of oxygen flow rates during the film deposition and post annealing in air atmosphere were explored. The V2O5 thin films were sputtered from vanadium target onto silicon wafer and glass slide substrates at room temperature. The as-deposited V2O5 thin films were annealed at 200°C under air atmosphere. The films were then examined for their crystallinity, physical microstructures, and optical transmission. The crystallinity and morphology of the films were investigated by grazing incident x-ray diffraction, atomic force microscopy, and field-emission scanning electron microscopy. The optical transmission was determined by UV-Vis Spectrophotometer. The results showed that the as-deposited films were amorphous, whereas the post annealed films indicated V2O5 phase in all samples. The increase in the oxygen flow rates during the deposition led to the decrease in the deposition rate, film thickness, and film surface roughness. In addition, the oxygen flow can increase the average transmission of the V2O5 thin films. The effects of the annealing treatment of the optical transmission spectra will be discussed.

Reciprocal Space Map Measurement of Ceramics Thin Films for Unequal Lattice Change at High Temperature

2020 ◽  
Vol 985 ◽  
pp. 218-222
Author(s):  
Atsushi Saiki ◽  
Shogo Miwa ◽  
Takashi Hashizume
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
Substrate Surface ◽  
Film Surface ◽  
Film Deposition ◽  
Reciprocal Space ◽  
Buffer Layers ◽  
Ionic Conductors ◽  
Thermal Shield

Ceria and zirconia are very important for their thermal, mechanical, and chemical stability, and their thin films have attracted much attention for applications such as buffer layers for growing electric devices, thermal-shield or optical coatings, corrosion-resistant coatings, oxygen sensors and ionic conductors for fuel cells. To investigate and control the thin film orientation and phase is important to improve those performances. In this study, the reciprocal space maps of CeO2/YSZ/Si(001) were obtained at high temperature by adding a heater to the sample stage. CeO2 and YSZ thin films were epitaxially grown samples. By measuring lattice constants at high temperature, it was conducted that axes of CeO2 and YSZ thin films parallel to the substrate surface showed smaller thermal coefficients than bulk reference and axes perpendicular to the surface showed larger thermal coefficients due to the underlayer and Si substrate. The distortion rate of the lattice of each film was small around at the film deposition temperature. And it could be controled the lattice parameter at the film surface by the film thickness. Therefore, when another thin film, for example, SrTiO3 is deposited on the CeO2 layer, the lattice change of CeO2 with increasing temperature may differ from that before depositing the top layer.

scholarly journals High-temperature stability of thermoelectric Ca3Co4O9 thin films

2015 ◽  
Vol 106 (14) ◽  
pp. 143903 ◽  
Author(s):  
P. Brinks ◽  
N. Van Nong ◽  
N. Pryds ◽  
G. Rijnders ◽  
M. Huijben
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Temperature Stability ◽  
High Temperature Stability

High temperature stability of indium tin oxide thin films

2002 ◽  
Vol 406 (1-2) ◽  
pp. 286-293 ◽  
Author(s):  
Otto J. Gregory ◽  
Qing Luo ◽  
Everett E. Crisman
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Oxide Thin Films

Dc Magnetron Reactive Sputtering of Low Stress Ain Piezoelectric Thin Films for Mems Application

1998 ◽  
Vol 546 ◽  
Author(s):  
Peter Hsieh ◽  
Rafael Reif ◽  
Brian Cunningham
Keyword(s):  
Thin Films ◽  
Integrated Circuit ◽  
Electromechanical Coupling ◽  
Film Deposition ◽  
Film Stress ◽  
Silicon Substrates ◽  
Mems Devices ◽  
Film Property ◽  
Deposition Parameters ◽  
Mems Fabrication

AbstractMany MEMS devices require piezoelectric excitation and readout to actuate and sense motion of mechanical structures. Aluminum nitride is advantageous for MEMS fabrication because it is compatible with silicon integrated circuit foundry impurity contamination requirements, can be deposited at low temperatures, provides a high piezoelectric coefficient, and is easily patterned using conventional photolithographic techniques. In this work, AIN thin films were deposited on silicon substrates for use in a MEMS silicon membrane ultrasonic resonator. The ultrasonic resonator is configured as a gravimetric sensing device for chemical detection. Issues of concern with regard to device performance and yield include the maximization of the electromechanical coupling constant (k2), film stress control, and film uniformity; these issues were addressed through a central composite design set of experiments to resolve the film property responses as a function of the deposition parameters. Film characterization was conducted with x-ray diffraction, spectroscopic ellipsometry, and surface profilometry. Optimization of film deposition parameters improved sensor performance and enabled further device miniaturization with the use of thinner films.

scholarly journals High Temperature Behavior of RuAl Thin Films on Piezoelectric CTGS and LGS Substrates

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1605 ◽  
Author(s):  
Marietta Seifert
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Cross Sections ◽  
Barrier Layer ◽  
High Vacuum ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Si Substrates ◽  
20 Nm

This paper reports on a significant further improvement of the high temperature stability of RuAl thin films (110 nm) on the piezoelectric Ca 3 TaGa 3 Si 2 O 14 (CTGS) and La 3 Ga 5 SiO 14 (LGS) substrates. RuAl thin films with AlN or SiO 2 cover layers and barriers to the substrate (each 20 nm), as well as a combination of both were prepared on thermally oxidized Si substrates, which serve as a reference for fundamental studies, and the piezoelectric CTGS, as well as LGS substrates. In some films, additional Al layers were added. To study their high temperature stability, the samples were annealed in air and in high vacuum up to 900 °C, and subsequently their cross-sections, phase formation, film chemistry, and electrical resistivity were analyzed. It was shown that on thermally oxidized Si substrates, all films were stable after annealing in air up to 800 °C and in high vacuum up to 900 °C. The high temperature stability of RuAl thin films on CTGS substrates was improved up to 900 °C in high vacuum by the application of a combined AlN/SiO 2 barrier layer and up to 800 °C in air using a SiO 2 barrier. On LGS, the films were only stable up to 600 °C in air; however, a single SiO 2 barrier layer was sufficient to prevent oxidation during annealing at 900 °C in high vacuum.

The High Temperature Stability and Relaxation of UHV/CVD SiGe Thin Films

1992 ◽  
Vol 280 ◽  
Author(s):  
S. R. Stiffler ◽  
C. L. Stanis ◽  
M. S. Goorsky ◽  
K. K. Chan
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Misfit Dislocation ◽  
Stability Criterion ◽  
Temperature Stability ◽  
Dislocation Nucleation ◽  
Misfit Dislocations ◽  
High Temperature Stability ◽  
Nucleation Barrier ◽  
The Stability

ABSTRACT:: High temperature (950°C) annealing is used to stimulate relaxation in UHV/CVD SiGe thin films. It is found that the films are stable to thicknesses which exceed the stability criterion of Matthews and Blakeslee [1] by a small amount. In unstable films, the misfit dislocation density increases with annealing time, reaching a maximum value. For films which exceed the empirical stability criterion by a relatively small amount, the misfit dislocations relax the film to a strain given by the film thickness and the empirical stability criterion. However, large remnant strains are observed when the relaxation process introduces relatively high dislocation densities (≳5 misfits/micron). Associated with large remnant strains are a marked propensity for dislocation banding and looping deep into the substrate with extended annealing. These results are discussed with respect to the magnitude of the misfit dislocation nucleation barrier and the energy associated with interactions among misfit dislocations.

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