A Technique for Deducing In-Plane Modulus and Coefficient of Thermal Expansion of a Supported Thin Film

2002 ◽  
Vol 124 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Martin Y. M. Chiang ◽  
Chwan K. Chiang ◽  
Wen-li Wu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Elastic Modulus ◽  
Coefficient Of Thermal Expansion ◽  
Thermal And Mechanical Properties ◽  
Reduction Scheme ◽  
Coupled Equations

A technique for determining the in-plane modulus and the coefficient of thermal expansion (CTE) of supported thin films has been developed. The modulus and CTE are calculated by solving two coupled equations that relate the curvature of film samples deposited on two different substrates to the thermal and mechanical properties of the constituents. In contrast with the conventional method used to calculate modulus and CTE, which involves differentiation of the thermal stress in the film, this new technique does not require the differentiation of the thermal stress, and can also provide the temperature-dependence of the in-plane CTE and elastic modulus of supported thin films. The data reduction scheme used for deducing CTE and elastic modulus is direct and reliable.

Determination of Mechanical Properties of Thin Film on Silicon Wafer

2003 ◽  
Author(s):  
Enboa Wu ◽  
Albert J. D. Yang ◽  
Ching-An Shao ◽  
C. S. Yen
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Silicon Wafer ◽  
Coefficient Of Thermal Expansion ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Bulk State

Nondestructive determination of Young’s modulus, coefficient of thermal expansion, Poisson ratio, and thickness of a thin film has long been a difficult but important issue as the film of micrometer order thick might behave differently from that in the bulk state. In this paper, we have successfully demonstrated the capability of determining all these four parameters at one time. This novel method includes use of the digital phase-shifting reflection moire´ (DPRM) technique to record the slope of wafer warpage under temperature drop condition. In the experiment, 1-um thick aluminum was sputtered on a 6-in silicon wafer. The convolution relationship between the measured data and the mechanical properties was constructed numerically using the conventional 3D finite element code. The genetic algorithm (GA) was adopted as the searching tool for search of the optimal mechanical properties of the film. It was found that the determined data for Young’s modulus (E), Coefficient of Thermal Expansion (CTE), Poisson ratio (ν), and thickness (h) of the 1.00 um thick aluminum film were 104.2Gpa, 38.0 ppm/°C, 0.38, and 0.98 um, respectively, whereas that in the bulk state were measured to be E=71.4 Gpa, CTE=23.0 ppm/°C, and ν=0.34. The significantly larger values on the Young’s modulus and the coefficient of thermal expansion determined by this method might be attributed to the smaller dislocation density due to the thin dimension and formation of the 5-nm layer of Al2O3 formed on top of the 1-um thick sputtered film. The Young’s Modulus and the Poisson ratio of this nano-scale Al2O3 film were then determined. Their values are consistent with the physical intuition of the microstructure.

scholarly journals Elastic modulus and coefficient of thermal expansion of piezoelectric Al1−xScxN (up to x = 0.41) thin films

APL Materials ◽  
2018 ◽  
Vol 6 (7) ◽  
pp. 076105 ◽  
Author(s):  
Yuan Lu ◽  
Markus Reusch ◽  
Nicolas Kurz ◽  
Anli Ding ◽  
Tim Christoph ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Coefficient Of Thermal Expansion

scholarly journals A Direct Comparison of Three Buckling-Based Methods to Measure the Elastic Modulus of Nanobiocomposite Thin Films

2020 ◽  
Author(s):  
Taylor C. Stimpson ◽  
Daniel A. Osorio ◽  
Emily D. Cranston ◽  
Jose Moran-Mirabal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
Input Parameter ◽  
Layer By Layer ◽  
Free Standing ◽  
Film Composition ◽  
Parameter Values

<p>To engineer tunable thin film materials, accurate measurement of their mechanical properties is crucial. However, characterizing the elastic modulus with current methods is particularly challenging for sub-micrometer thick films and hygroscopic materials because they are highly sensitive to environmental conditions and most methods require free-standing films which are difficult to prepare. In this work, we directly compared three buckling-based methods to determine the elastic moduli of supported thin films: 1) biaxial thermal shrinking, 2) uniaxial thermal shrinking, and 3) the mechanically compressed, strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) method. Nanobiocomposite model films composed of cellulose nanocrystals (CNCs) and polyethyleneimine (PEI) were assembled using layer-by-layer deposition to control composition and thickness. The three buckling-based methods yielded the same trends and comparable values for the elastic moduli of each CNC-PEI film composition (ranging from 15 – 44 GPa, depending on film composition). This suggests that the methods are similarly effective for the quantification of thin film mechanical properties. Increasing the CNC content in the films statistically increased the modulus, however, increasing the PEI content did not lead to significant changes. The standard deviation of elastic moduli determined from SIEBIMM was 2-4 times larger than for thermal shrinking, likely due to extensive cracking and partial film delamination. In light of these results, biaxial thermal shrinking is recommended as the method of choice because it affords the simplest implementation and analysis and is the least sensitive to small deviations in the input parameter values, such as film thickness or substrate modulus.</p>

Hrtem Study of Interface Structure Of Heteroepitaxially Grown GaAs Thin Films on GaAs(l00)

1998 ◽  
Vol 4 (S2) ◽  
pp. 624-625
Author(s):  
Z.R. Dai ◽  
S.R. Chegwidden ◽  
F.S. Ohuchi
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Second Harmonic ◽  
Interface Structure ◽  
Thermal And Mechanical Properties ◽  
Surface And Interface ◽  
Device Structures ◽  
New Generation ◽  
Related Compounds

GaSe, a member of the III-VI compound semiconductors, and its related compounds have recently gained an considerable attention because of their high non-linear optical coefficients in the infrared ranges, making them candidates for second harmonic generation (SHG) materials[l,2]. While the optical properties of those materials in bulk form are quite promising, poor thermal and mechanical properties preclude their easy applications. In thin film devices, the thermal and mechanical properties are dominated by those of the substrate, therefore, heteroepitaxially grown thin films of GaSe and related materials on substrates such as GaAs, Si and A12O3 should enable their application in device structures. Development of such new generation of materials, however, require fundamental knowledge about the surface and interface structure that play decisive roles in the thin film crystallinity and materials properties.

Measuring the elastic modulus and residual stress of freestanding thin films using nanoindentation techniques

2009 ◽  
Vol 24 (9) ◽  
pp. 2974-2985 ◽  
Author(s):  
Erik G. Herbert ◽  
Warren C. Oliver ◽  
Maarten P. de Boer ◽  
George M. Pharr
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Dimensional Analysis ◽  
Experimental Verification ◽  
Cu Films ◽  
Proposed Model ◽  
The Difference

A new method is proposed to determine the elastic modulus and residual stress of freestanding thin films based on nanoindentation techniques. The experimentally measured stiffness-displacement response is applied to a simple membrane model that assumes the film deformation is dominated by stretching as opposed to bending. Dimensional analysis is used to identify appropriate limitations of the proposed model. Experimental verification of the method is demonstrated for Al/0.5 wt% Cu films nominally 22 µm wide, 0.55 µm thick, and 150, 300, and 500 µm long. The estimated modulus for the four freestanding films match the value measured by electrostatic techniques to within 2%, and the residual stress to within 19.1%. The difference in residual stress can be completely accounted for by thermal expansion and a modest change in temperature of 3 °C. Numerous experimental pitfalls are identified and discussed. Collectively, these data and the technique used to generate them should help future investigators make more accurate and precise measurements of the mechanical properties of freestanding thin films using nanoindentation.

Study of SiC’s Mechanical Property Variance Caused by Film Thickness

2015 ◽  
Vol 645-646 ◽  
pp. 400-404
Author(s):  
Zong Lei Jiao ◽  
Jian Zhu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Chemical Vapor Deposition ◽  
Elastic Modulus ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Indentation Load

The mechanical properties of SiC thin films deposited by chemical vapor deposition process on silicon substrate are studied using nanoindentation techniques. The SiC thin films are of three different thicknesses: 1.6μm、4.5μm、9μm. In this study, nanoindentation method is preferred due to its reliability and accuracy on determining mechanical properties from indentation load-displacement data. The mechanical properties of elastic modulus and hardness are characterized. 1.6μm SiC thin film has the following values: E=345.73Gpa, H=33.71Gpa; 4.5μm SiC thin film has the following values: E=170.18Gpa, H=10.33Gpa; 9μm SiC thin film: E=167.96Gpa, H=9.48Gpa

scholarly journals Near-Zero Thermal Expansion in Freeze-Cast Composite Materials

Ceramics ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Sarah Ellis ◽  
Carl Romao ◽  
Mary White
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Ceramic Composites ◽  
Growth Direction ◽  
Thermal And Mechanical Properties ◽  
Ice Growth ◽  
Low Thermal Expansion ◽  
Hardness Values

Most materials expand when heated, which can lead to thermal stress and even failure. Whereas thermomiotic materials exhibit negative thermal expansion, the creation of materials with near-zero thermal expansion presents an ongoing challenge due to the need to optimize thermal and mechanical properties simultaneously. The present work describes the preparation and properties of polymer–ceramic composites with low thermal expansion. Ceramic scaffolds, prepared by freeze-casting of low-thermal-expansion Al2W3O12, were impregnated with poly(methylmethacrylate) (PMMA). The resulting composites can have a coefficient of thermal expansion as low as 2 × 10−6 K−1, and hardness values of 4.0 ± 0.3 HV/5 (39 ± 3 MPa) and 16 ± 3 HV/5 (160 ± 30 MPa) parallel and perpendicular to the ice growth, respectively. The higher hardness perpendicular to the ice growth direction indicates that the PMMA is acting to improve the mechanical properties of the composite.

Mechanical and Thermophysical Properties of Silicon Nitride Thin Films at High Temperatures Using In-Situ Mems Temperature Sensors

1998 ◽  
Vol 546 ◽  
Author(s):  
Patricia Nieva ◽  
Haruna Tada ◽  
Paul Zavracky ◽  
George Adams ◽  
Ioannis Miaoulis ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Expansion ◽  
Silicon Nitride ◽  
High Temperatures ◽  
Thermophysical Properties ◽  
Microelectromechanical Systems ◽  
Coefficient Of Thermal Expansion ◽  
Maximum Temperature ◽  
Wide Range

AbstractThe optimization of microelectronic devices and Microelectromechanical Systems (MEMS) technology depends on the knowledge of the mechanical and thermophysical properties of the thin film materials used to fabricate them. The thickness, stoichiometry, structure and thermal history can affect the properties of thin films causing their mechanical and thermophysical properties to diverge from bulk values. Moreover, it is known that the mechanical and thermophysical properties of thin films vary considerably at different temperatures. Bulk properties of semiconductors have been characterized over a wide range of temperatures; however there is limited information on thin film properties of silicon-based compounds such as silicon nitride, specially at high temperatures. In our work, MEMS devices designed to record the localized maximum temperature during high temperature thermal processes, which we call Breaking T-MEMS, will be presented as a way to determine some of the mechanical properties (Young's modulus and fracture strength) and thermophysical properties (coefficient of thermal expansion) of silicon-rich nitride thin films at high temperatures.The Breaking T-MEMS device consists of a thin film bridge suspended over a substrate. During testing, the devices are thermally loaded in tension by heating the sample. The low coefficient of thermal expansion of the film relative to that of the substrate causes the thin film bridge to break at a specific temperature. Through a combination of indirect experimental measurements, analytical expressions, numerical and statistical analysis, and if the experiments are conducted using at least two different substrates of known temperaturedependent coefficients of thermal expansion, some of the material properties of the film can be calculated from the breaking temperatures of various devices. The two candidate materials for the substrate are silicon and aluminum oxide (sapphire).

scholarly journals Coefficient of thermal expansion and elastic modulus of thin films

1999 ◽  
Vol 86 (9) ◽  
pp. 4936-4942 ◽  
Author(s):  
M. M. de Lima ◽  
R. G. Lacerda ◽  
J. Vilcarromero ◽  
F. C. Marques
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Coefficient Of Thermal Expansion
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