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.

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.

Effect of Precursor Sol Ageing on Sol-Gel Derived Ruthenium Oxide Thin Films

1999 ◽  
Vol 606 ◽  
Author(s):  
S. Bhaskar ◽  
S. B. Majumder ◽  
P. S. Dobal ◽  
R. S. Katiyar ◽  
A. L. M. Cruz ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Ruthenium Oxide ◽  
Precursor Solution ◽  
Silicon Substrates ◽  
Solution Deposition ◽  
Precursor Material ◽  
Afm Analysis

AbstractIn the present work we have optimized the process parameters to yield homogeneous, smooth ruthenium oxide (RuO2) thin films on silicon substrates by a solution deposition technique using RuCl3.×.H2O as the precursor material. Films were annealed in a temperature range of 300°C to 700°C, and it was found that RuO2 crystallizes at a temperature as low as 400°C. The crystallinity of the films improves with increased annealing temperature and the resistivity decreases from 4.86µΩ-m (films annealed at 400°C) to 2.94pµΩ (films annealed at 700°C). Ageing of the precursor solution has a pronounced effect on the measured resistivities of RuO2 thin films. It was found that the measured room temperature resistivities increases from 2.94µΩ-m to 45.7µΩ-m when the precursor sol is aged for aged 60 days. AFM analysis on the aged films shows that the grain size and the surface roughness of the annealed films increase with the ageing of the precursor solution. From XPS analysis we have detected the presence of non-transformed RuCl3 in case of films prepared from aged solution. We propose, that solution ageing inhibits the transformation of RuCl3 to RuO2 during the annealing of the films. The deterioration of the conductivity with solution ageing is thought to be related with the chloride contamination in the annealed films.

Structural and mechanical properties of La 1/3 NbO 3 and La 1/3 TaO 3 thin films prepared by chemical solution deposition

2017 ◽  
Vol 35 (11) ◽  
pp. 1115-1125 ◽  
Author(s):  
Helena Brunckova ◽  
Lubomir Medvecky ◽  
Alexandra Kovalcikova ◽  
Martin Fides ◽  
Erika Mudra ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Chemical Solution Deposition ◽  
Chemical Solution ◽  
Solution Deposition

Effects of dynamic indentation on the mechanical response of materials

2008 ◽  
Vol 23 (6) ◽  
pp. 1604-1613 ◽  
Author(s):  
M.J. Cordill ◽  
N.R. Moody ◽  
W.W. Gerberich
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Mechanical Response ◽  
Length Scale ◽  
Polycrystalline Nickel ◽  
Dynamic Indentation ◽  
Crystalline Materials ◽  
Fused Quartz ◽  
Hardness Values ◽  
Measured Hardness

Dynamic indentation techniques are often used to determine mechanical properties as a function of depth by continuously measuring the stiffness of a material. The dynamics are used by superimposing an oscillation on top of the monotonic loading. Of interest was how the oscillation affects the measured mechanical properties when compared to a quasi-static indent run at the same loading conditions as a dynamic. Single crystals of nickel and NaCl as well as a polycrystalline nickel sample and amorphous fused quartz and polycarbonate have all been studied. With respect to dynamic oscillations, the result is a decrease of the load at the same displacement and thus lower measured hardness values of the ductile crystalline materials. It has also been found that the first 100 nm of displacement are the most affected by the oscillating tip, an important length scale for testing thin films, nanopillars, and nanoparticles.

Electrical Properties of Perovskite-Based Ferroelectric Thin Films Modified Using Rare-Earth Elements

2006 ◽  
Vol 320 ◽  
pp. 49-52
Author(s):  
Hiroshi Uchida ◽  
Hiroshi Nakaki ◽  
Hiroshi Funakubo ◽  
Seiichiro Koda
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Electrical Properties ◽  
Lead Zirconate Titanate ◽  
Remanent Polarization ◽  
Lead Zirconate ◽  
Solution Deposition ◽  
Si Substrates ◽  
Crystal Anisotropy ◽  
Insulating Properties

The electrical properties of perovskite-based ferroelectric films were improved by ion modification using rare-earth cations. Thin films of rare-earth-modified lead zirconate titanate [Pb(Zr,Ti)O3] were fabricated on (111)Pt/Ti/SiO2/(100)Si substrates by a chemical solution deposition technique. The substitution of volatile cations in the simple-perovskite oxides, such as Pb2+ in Pb(Zr,Ti)O3 films, enhanced the insulating properties of the film. The crystal anisotropy of the Pb(Zr,Ti)O3 film could be controlled by varying the species and the amount of replacing cations to enhance the spontaneous polarization. Thus, ion modification using Dy3+ cation could enhance the remanent polarization of Pb(Zr,Ti)O3 film consequently.

Island Structured Dielectric Thin Films by Scalable Self-Assembly

2010 ◽  
Vol 1253 ◽  
Author(s):  
Sharath Sriram ◽  
Madhu Bhaskaran ◽  
Arnan Mitchell
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Self Assembly ◽  
Complex Oxide ◽  
Lead Zirconate ◽  
Dielectric Films ◽  
Silicon Substrates ◽  
Preferential Growth ◽  
Dielectric Thin Films ◽  
Complex Chemistry

AbstractA self-assembly driven process to synthesize island-structured dielectric films is presented. An intermetallic reaction in platinized silicon substrates provides preferential growth sites for the complex oxide dielectric (strontium-doped lead zirconate titanate) layer. Microscopy and spectroscopy analyses have been used to propose a mechanism for this structuring process. This provides a simple and scalable process to synthesize films with increased surface area for sensors, especially those materials with a complex chemistry.

Measurements of Piezoelectric Constant D33 of Lead Zirconate Titanate (PZT) Through Use of a Mini Impact Hammer

2009 ◽  
Author(s):  
Qing Guo ◽  
G. Z. Cao ◽  
I. Y. Shen
Keyword(s):  
Thin Films ◽  
Boundary Conditions ◽  
Lead Zirconate Titanate ◽  
Low Cost ◽  
Lead Zirconate ◽  
Piezoelectric Constant ◽  
Impulsive Force ◽  
Sensors And Actuators ◽  
Aspect Ratios ◽  
Zirconate Titanate

Lead Zirconate Titanate Oxide (PbZrxTi1−xO3 or PZT) is a piezoelectric material widely used as sensors and actuators. For microactuators, PZT often appears in the form of thin films to maintain proper aspect ratios. This paper is to present a simple and low-cost method to measure piezoelectric constant d33 of PZT thin films, which is a major challenge encountered in the actuator development. We use an impact hammer with a sharp tip to generate an impulsive force that acts on the PZT film. The impulsive force and the responding voltage are then measured to calculate the piezoelectric constant d33. The impulsive force has large enough amplitude so that a good signal-to-noise ratio can be maintained. Furthermore, the impulsive force has extremely short duration, so the discharge effect (i.e., the time constant effect) of the PZT circuit can be ignored. Preliminary testing on bulk PZT through this new method leads to two conclusions. Firstly, boundary conditions of the specimen are critical. In particular, the specimen must be securely fastened. Since the impulsive load only acts on a tiny area, loose boundary conditions can introduce spurious results from other piezoelectric constant d31. Secondly, size of the specimen is critical. Specimen of smaller size leads to more accurate measurements of the piezoelectric constant d33.

Electrical and Optical Properties of LiNbO3/CaCu3Ti4O12 Heterostructures on Si

2015 ◽  
Vol 1805 ◽  
Author(s):  
Javad R. Gatabi ◽  
Kevin A. Lyon ◽  
Shafiqur Rahman ◽  
Hanu Arava ◽  
Juan S Rojas-Ramirez ◽  
...  
Keyword(s):  
Thin Films ◽  
Cost Effective ◽  
Deposition Process ◽  
Structural Quality ◽  
Silicon Substrates ◽  
Solution Deposition ◽  
Effective Spin ◽  
Capacitance Variation ◽  
Crystallization Conditions

ABSTRACTThe role of ferroelectric LiNbO3 (LNB) in altering the frequency dependence of the capacitance of CaCu3Ti4O12 (CCTO) thin films has been investigated. A cost effective spin coating deposition process was used to integrate the oxide heterostructures onto silicon substrates. This study showed that the frequency stability of the CCTO/LNB structure was much improved when the crystallization conditions and physical dimension of each layer were optimized. To integrate this structure with current silicon technology, heterostructures of CCTO and LNB thin films were fabricated on HF terminated Si using chemical solution deposition. It was found that the order of deposition of the two layers was important for the structural quality of the heterostructures with the CCTO layer followed by the LNB layer being the preferred structure. In addition to improvement of the capacitance variation with frequency, the heterostructures also provide a path to tuning the frequency of operation.

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.

Sign in / Sign up

Export Citation Format

Share Document