Mechanical Properties of Ultrananocrystalline Diamond Thin Films for MEMS Applications

2002 ◽  
Vol 741 ◽  
Author(s):  
H.D. Espinosa ◽  
B. Peng ◽  
K.-H. Kim ◽  
B.C. Prorok ◽  
N. Moldovan ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Moduli ◽  
Microelectromechanical Systems ◽  
Nanosized Particles ◽  
Good Reproducibility ◽  
Fracture Properties ◽  
Ultrananocrystalline Diamond ◽  
Mems Fabrication ◽  
Membrane Deflection

ABSTRACTMicrocantilever deflection and the membrane deflection experiment (MDE) were used to examine the elastic and fracture properties of ultrananocrystalline diamond (UNCD) thin films in relation to their application to microelectromechanical systems (MEMS). Freestanding microcantilevers and membranes were fabricated using standard MEMS fabrication techniques adapted to our UNCD film technology. Elastic moduli measured by both methods described above are in agreement, with the values being in the range 930 and 970 GPa with both techniques showing good reproducibility. The MDE test showed fracture strength to vary from 3.95 to 5.03 GPa when seeding was performed with ultrasonic agitation of nanosized particles.

Elastic Properties of Artificially Layered Thin Films

1987 ◽  
Vol 103 ◽  
Author(s):  
Robert C. Cammarata
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Composite Materials ◽  
Elastic Properties ◽  
Elastic Moduli ◽  
Metallic Thin Films ◽  
Theoretical Understanding ◽  
Composition Modulation

ABSTRACTEnhancements in the elastic moduli by factors of two or more in compositionally modulated metallic thin films have been observed for a certain range of composition modulation wavelengths. The experimental and theoretical understanding of this phenomenon, known as the supermodulus effect, is reviewed. Also, the mechanical properties of other artificially layered and composite materials are discussed and compared with the behavior of metallic superlattice thin films.

Mechanical properties of ultrananocrystalline diamond thin films relevant to MEMS/NEMS devices

2003 ◽  
Vol 43 (3) ◽  
pp. 256-268 ◽  
Author(s):  
H. D. Espinosa ◽  
B. C. Prorok ◽  
B. Peng ◽  
K. H. Kim ◽  
N. Moldovan ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Ultrananocrystalline Diamond ◽  
Diamond Thin Films

Size effect on the mechanical properties of microfabricated polysilicon thin films

2001 ◽  
Vol 16 (8) ◽  
pp. 2223-2228 ◽  
Author(s):  
J. N. Ding ◽  
Y. G. Meng ◽  
S. Z. Wen
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Size Effect ◽  
Surface Area ◽  
Fracture Strength ◽  
Size Effects ◽  
Microelectromechanical Systems ◽  
Governing Parameter ◽  
Average Value ◽  
Microtensile Test

A new microtensile test device using a magnetic-solenoid force actuator was developed to evaluate the mechanical properties of microfabricated polysilicon thin films that were 100–660 mm long, 20–200 μm wide, and 2.4-μm thick. It was found that the measured average value of Young's modulus, 164 GPa ± 1.2 GPa, falls within the theoretical bounds. The average fracture strength is 1.36 GPa with a standard deviation of 0.14 GPa, and the Weibull modulus is 10.4–11.7. Statistical analysis of the specimen size effects on the tensile strength predicated the size effects on the length, the surface area, and the volume of the specimens. The fracture strength increases with an increase of the ratio of surface area to volume. In such cases, the size effect can be corrected to the ratio of the surface area to volume as the governing parameter. The test data accounts for the uncertainties in mechanical properties and may be used to enhance the reliability and design of polysilicon microelectromechanical systems devices.

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>

Nanoindentation Measurements on Low-k Porous Silica Thin Films Spin Coated on Silicon Substrates

2003 ◽  
Vol 125 (4) ◽  
pp. 361-367 ◽  
Author(s):  
Xiaoqin Huang ◽  
Assimina A. Pelegri
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Young's Modulus ◽  
Porous Silica ◽  
Silicon Substrates ◽  
Silica Thin Films ◽  
Low K

MEMS (MicroElectroMechanical Systems) are composed of thin films and composite nanomaterials. Although the mechanical properties of their constituent materials play an important role in controlling their quality, reliability, and lifetime, they are often found to be different from their bulk counterparts. In this paper, low-k porous silica thin films spin coated on silicon substrates are studied. The roughness of spin-on coated porous silica films is analyzed with in-situ imaging and their mechanical properties are determined using nanoindentation. A Berkovich type nanoindenter, of a 142.3 deg total included angle, is used and continuous measurements of force and displacements are acquired. It is shown, that the measured results of hardness and Young’s modulus of these films depend on penetration depth. Furthermore, the film’s mechanical properties are influenced by the properties of the substrate, and the reproduction of the force versus displacement curves depends on the quality of the thin film. The hardness of the studied low-k spin coated silica thin film is measured as 0.35∼0.41 GPa and the Young’s modulus is determined as 2.74∼2.94 GPa.

On the Role of the Underlying Microstructure on the Mechanical Properties of Microelectromechanical Systems (MEMS) Materials

2000 ◽  
Vol 657 ◽  
Author(s):  
G. F. Dirras ◽  
G. Coles ◽  
A. J. Wagner ◽  
S. Carlo ◽  
C. Newman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Mechanical Properties ◽  
Microelectromechanical Systems ◽  
Chemical Vapor ◽  
Xrd Analysis ◽  
Transmission Electron ◽  
Columnar Grains ◽  
Pressure Chemical ◽  
20 Nm

ABSTRACTThe microstructure of Low Pressure Chemical Vapor Deposition (LPCVD) Polycrystalline silicon (Polysilicon) thin films was investigated by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and Auger electron spectroscopy (AES). SEM characterization of tensile tested samples showed a brittle like-rupture, along with grooves located at the surface sides of the sample. TEM investigations of as-deposited samples showed equiaxed or fully columnar grains bridging from the bottom to the top of the films. A microstructural coarsening was observed with annealing. In the as-deposited state, the films exhibited a {110} texture as showed by the XRD analysis. The films' top and bottom surfaces were observed to be smooth with a roughness (standard deviation) of about 11nm and 20 nm respectively. A chemical analysis of the thin films showed the presence of carbon and oxygen impurities on the surface and oxygen through the sample as observed in the depth profile. The hypothetical influence of these findings is subsequently discussed in relation to the measured mechanical properties.

Mechanical Properties and Adhesion of PZT Thin Films for MEMS

1999 ◽  
Vol 594 ◽  
Author(s):  
J. M. Jungk ◽  
B. T. Crozier ◽  
A. Bandyopadhyay ◽  
N. R. Moody ◽  
D. F. Bahr
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Failure Modes ◽  
Microelectromechanical Systems ◽  
Mechanical Response ◽  
Lead Zirconate ◽  
Silicon Substrates ◽  
Sensors And Actuators ◽  
Solution Deposition ◽  
Ability To Act

AbstractPiezoelectric films are attractive materials for use in microelectromechanical systems (MEMS) due to their ability to act as both sensors and actuators. One of the primary modes of deformation is the deflection of lead zirconate titantate (PZT) beams and membranes, where the adhesion of the film is critical for the reliability of the device. Thin films of PZT between 250 and 750 nm have been grown via solution deposition routes onto platinized silicon substrates. The films have been tested using nanoindentation techniques. Two failure mechanism in these films have been observed Indentation induced delamination at the PZT-Pt interface occurs after the indenter tip is removed from the film when loads between 1 and 10 mN are applied to the sample, and at large loads (>75 mN) failure can be generated between the underlying oxide film and the silicon substrate while the tip is still engaged with the sample. Since each of these failure modes has a different mechanics solution, the results are compared to determine adhesion energy of the films. Fracture around the delaminated regions has been examined using scanning probe and electron microscopy. Freestanding PZT membranes above micromachined cavities have been mechanically deformed to examine the mechanical response and failure modes in these structures. The adhesion of the PZT improves with increased percent crystallization due to the introduction of residual tensile stresses. Processing, mechanical properties, and failure modes in these devices will be discussed.

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