Origins and evolution of stress development in sol-gel derived thin layers and multideposited coatings of lead titanate

1998 ◽  
Vol 83 (4) ◽  
pp. 2291-2296 ◽  
Author(s):  
S. S. Sengupta ◽  
S. M. Park ◽  
D. A. Payne ◽  
L. H. Allen
Keyword(s):  
Lead Titanate ◽  
Sol Gel ◽  
Thin Layers ◽  
Stress Development

Integrated electroceramics: densification and stress development in sol-gel derived thin layers

1997 ◽  
Vol 14 (1-4) ◽  
pp. 193-200 ◽  
Author(s):  
Samit S. Sengupta ◽  
Sang M. Park ◽  
David A. Payne
Keyword(s):  
Sol Gel ◽  
Thin Layers ◽  
Stress Development

Densification and Evolution of Stress Development in Solution Derived PbZr0.53Ti0.47O3 Thin Layers

1999 ◽  
Vol 596 ◽  
Author(s):  
Sang M. Park
Keyword(s):  
Sol Gel ◽  
Film Plane ◽  
Thin Layers ◽  
Silicon Substrates ◽  
Sintering Process ◽  
Stress Development ◽  
Insertion Method ◽  
Gel Processing ◽  
Reflectance Measurements

AbstractStress development in thin layers of PbZr0.53Ti0.47O3 (PZT) and PbTiO3 (PT) prepared by sol-gel processing was monitored by in situ laser reflectance measurements. Layers were spin coated onto silicon substrates and thermally cycled to 600°C and 650°C. The shrinkage normal to the film plane was determined by in situ ellipsometry and scanning electron microscopy. Both PZT and PT multilayers showed a similar stress behavior on heating, but quite different behavior on cooling. As the film became dense at high temperatures, total stress was dominated by the thermal expansion mismatch between the oxide layer and the substrate. On cooling, the PT multilayers, which already crystallized into the perovskite structure, ended nearly stress free at room temperature, whereas mostly amorphous PZT multilayers were under a high tensile stress. Densification in PZT layers appeared to occur between 370°C and 520°C. At near 370°C the shrinkage mode for a single PZT layer was also observed to change substantially. A two-stage sintering process employing 450°C-sintering and 650°C-crystallization was found to be as effective as direct furnace insertion method in producing a dense film.

Preferred Orientations for Sol-Gel Derived Plzt Thin Layers

1993 ◽  
Vol 310 ◽  
Author(s):  
Toshihiko Tani ◽  
Zhengkui Xu ◽  
David A. Payne
Keyword(s):  
Heat Treatment ◽  
Surface Energy ◽  
Sol Gel ◽  
Nucleation And Growth ◽  
Thin Layers ◽  
Energy Conditions ◽  
Chemical Characteristics ◽  
Interfacial Chemistry ◽  
Si Substrates

AbstractPLZT thin layers were deposited onto various substrates by sol-gel methods, and crystallized under different conditions and substrate treatments. Relationships are given for the chemical characteristics of the substrate's surface and the preferred orientations which develop on heat treatment. A preferred (111) orientation always developed for perovskite crystallized on Pt layers which contained Ti on the surface. This was attributed to the formation of Pt3Ti and the role of heteroepitaxial nucleation and growth sites. In addition, a preferred (100) orientation was also obtained on unannealed Pt/Ti/SiO2/Si substrates which were free of Ti on the surface. This was attributed to self-textured growth with flat faces striving for minimum surface energy conditions. The results are discussed in terms of the importance of interfacial chemistry on the control of texture for crystallization of PLZT thin layers on coated substrates.

High-Speed Synthesis and Electric Properties of Magnesium Doped Lead Titanate Ceramics

2007 ◽  
Vol 121-123 ◽  
pp. 149-152
Author(s):  
Liang Sheng Qiang ◽  
Dong Yan Tang ◽  
Xing Hong Zhang ◽  
L. Jin
Keyword(s):  
Lead Titanate ◽  
High Speed ◽  
Sintering Temperature ◽  
Water Solution ◽  
Sol Gel ◽  
Electric Properties ◽  
Synthesis Process ◽  
Pure Lead ◽  
Alcohol Water ◽  
Titanate Ceramics

By adding methyl alcohol/water solution with certain concentration into sol to hydrolysis directly and sintering the fresh sol directly, lead titanate(PbTiO3) ceramics doped with magnesium are prepared by using magnesium acetate as doper to prohibit the disadvantages contained in conventional sol-gel method, such as low hydrolytic rate, high sintering temperature, long preparation period. The changes of structure, microstructure, synthesis process and electric properties of modified ceramics are studied in detail. The sizes and morphology of high purely and high density magnesium doped lead titanate nanocrystals thus obtained are observed by TEM photographs and the structures and affection of sintering temperature of to lattice constant and sizes of nanocrystals are detected by XRD. Electric properties detection results show that doped lead titanate ceramics exhibite excellent dielectric, ferroelectric and pyroelectric properties compare with pure lead titanate.

Sol-Gel Derived Silica Layers for Low-k Dielectrics Applications

2000 ◽  
Vol 612 ◽  
Author(s):  
Sylvie Acosta ◽  
André Ayral ◽  
Christian Guizard ◽  
Charles Lecornec ◽  
Gérard Passemard ◽  
...  
Keyword(s):  
Average Pore Size ◽  
Sol Gel ◽  
Porous Silica ◽  
Thin Layers ◽  
Gaseous Ammonia ◽  
Potential Candidate ◽  
Average Pore ◽  
Synthesis Strategy ◽  
Silica Layers ◽  
Highly Porous

AbstractPorous silica exhibits attractive dielectric properties, which make it a potential candidate for use as insulator into interconnect structures. A new way of preparation of highly porous silica layers by the sol-gel route was investigated and is presented. The synthesis strategy was based on the use of common and low toxicity reagents and on the development of a simple process without gaseous ammonia post-treatment or supercritical drying step. Defect free layers were deposited by spin coating on 200 mm silicon wafers and characterized. Thin layers with a total porosity larger than 70% and an average pore size of 5 nm were produced. The dielectric constant measured under nitrogen flow on these highly porous layers is equal to ∼ 2.5, which can be compared to the value calculated from the measured porosity, ∼ 1.9. This difference is explained by the presence of water adsorbed on the hydrophilic surface of the unmodified silica.

ChemInform Abstract: Preparation of Undoped Lead Titanate Ceramics via Sol-Gel Processing.

ChemInform ◽  
2010 ◽  
Vol 30 (19) ◽  
pp. no-no
Author(s):  
Sunuk Kim ◽  
Myong-cheol Jun ◽  
Soon-cheol Hwang
Keyword(s):  
Lead Titanate ◽  
Sol Gel ◽  
Titanate Ceramics ◽  
Gel Processing

Stress Development in Low Dielectric Constant Silica Films During Drying and Heating Process

1999 ◽  
Vol 594 ◽  
Author(s):  
Mengcheng Lu ◽  
C. Jeffrey Brinker
Keyword(s):  
Dielectric Constant ◽  
Tensile Stress ◽  
Sol Gel ◽  
Low Dielectric Constant ◽  
Heating Process ◽  
Residual Tensile Stress ◽  
Silica Films ◽  
Stress Development ◽  
Low Dielectric

AbstractLow dielectric constant silica films are made using a surfactant templated sol-gel process (K∼2.5) or an ambient temperature and pressure aerogel process (K∼1.5). This paper will present the in-situ measurement and analysis of stress development during the making of these films, from the onset of drying till the end of heating. The drying stress is measured by a cantilever beam technique; the thermal stress is measured by monitoring the wafer curvature using a laser deflection method. During the course of drying, the surfactant templated films experience a low drying stress due to the influence of the surfactant on surface tension and extent of siloxane condensation. The aerogel films first develop a biaxial tensile stress due to solidification and initial drying. At the final stage of drying where the drying stress vanishes, dilation of the film recreates the porosity of the wet gel state, reducing the residual stress to zero. For the surfactant templated films, very small residual tensile stress remains after the heat treatment is finished (∼30MPa). Aerogel film has almost no measurable stress developed in the calcination process. In situ spectroscopic ellipsometry analysis during drying and heating, and TGA/DTA are all used to help understand the stress development.

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