scholarly journals Simple Non-Destructive Method of Ultrathin Film Material Properties and Generated Internal Stress Determination Using Microcantilevers Immersed in Air

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 486 ◽  
Author(s):  
Ivo Stachiv ◽  
Lifeng Gan
Keyword(s):  
Internal Stress ◽  
Quality Factor ◽  
Ultrathin Films ◽  
Material Properties ◽  
Ultrathin Film ◽  
Film Deposition ◽  
Film Material ◽  
Quality Factors ◽  
Resonant Frequencies ◽  
Film Density

Recent progress in nanotechnology has enabled to design the advanced functional micro-/nanostructures utilizing the unique properties of ultrathin films. To ensure these structures can reach the expected functionality, it is necessary to know the density, generated internal stress and the material properties of prepared films. Since these films have thicknesses of several tens of nm, their material properties, including density, significantly deviate from the known bulk values. As such, determination of ultrathin film material properties requires usage of highly sophisticated devices that are often expensive, difficult to operate, and time consuming. Here, we demonstrate the extraordinary capability of a microcantilever commonly used in a conventional atomic force microscope to simultaneously measure multiple material properties and internal stress of ultrathin films. This procedure is based on detecting changes in the static deflection, flexural and torsional resonant frequencies, and the corresponding quality factors of the microcantilever vibrating in air before and after film deposition. In contrast to a microcantilever in vacuum, where the quality factor depends on the combination of multiple different mechanical energy losses, in air the quality factor is dominated just by known air damping, which can be precisely controlled by changing the air pressure. Easily accessible expressions required to calculate the ultrathin film density, the Poisson’s ratio, and the Young’s and shear moduli from measured changes in the microcantilever resonant frequencies, and quality factors are derived. We also show that the impact of uncertainties on determined material properties is only minor. The validity and potential of the present procedure in material testing is demonstrated by (i) extracting the Young’s modulus of atomic-layer-deposited TiO2 films coated on a SU-8 microcantilever from observed changes in frequency response and without requirement of knowing the film density, and (ii) comparing the shear modulus and density of Si3N4 films coated on the silicon microcantilever obtained numerically and by present method.

Analysis of a circular microstrip antenna on isotropic or uniaxially anisotropic substrate using neurospectral approach

2013 ◽  
Vol 33 (1/2) ◽  
pp. 567-580 ◽  
Author(s):  
Sami Bedra ◽  
Siham Benkouda ◽  
Tarek Fortaki
Keyword(s):  
Resonant Frequency ◽  
Quality Factor ◽  
Microstrip Antenna ◽  
Numerical Results ◽  
Spectral Domain ◽  
Quality Factors ◽  
Resonant Frequencies ◽  
Content Type ◽  
Anisotropic Substrate ◽  
Circular Microstrip Antenna

Purpose – The paper aims to propose an artificial neural network (ANN) in conjunction with spectral domain formulation for fast and accurate determination of the resonant frequency and quality factor of circular microstrip antenna printed on isotropic or anisotropic substrate. This neurospectral approach reduces the problem complexity. Design/methodology/approach – The moment method implemented in the spectral domain provides good accuracy but its computational cost is high due to the evaluation of the slowly decaying integrals and the iterative nature of the solution process. The paper introduces the electromagnetic knowledge combined with ANN in the analysis of circular microstrip antenna on isotropic or uniaxially anisotropic substrate to reduce the complexity of the spectral approach and to minimize the CPU time necessary to obtain the numerical results. Findings – The resonant frequency results obtained from the neural model are in very good agreement with the experimental and theoretical results available in the literature. Finally, numerical results for the substrate anisotropy effect on the resonant frequency, quality factor and radiation pattern are also presented. Originality/value – The paper develops fast and accurate model based on ANN technique to calculate the resonant frequencies and quality factors of circular microstrip antennas. ANN is used to model the relationship between the parameters of the microstrip antenna and the resonant frequencies and quality factors obtained from the spectral domain approach. This relatively simple model allows designers to predict accurately the resonant frequencies and quality factors for a given design without having to develop or run the spectral method codes themselves. The main advantages of the method are: less computing time than the spectral model, results with accuracy equivalent to that of full-wave models and cost effectiveness, since the client can use a simple PC for implementation. Another advantage of the proposed ANN model is that it takes into account the uniaxial anisotropy in the substrate without increasing the network size. This is done by combining ANN with electromagnetic knowledge.

FTIR Ellipsometry Analysis of the Internal Stress in SiC/Si MEMS

2007 ◽  
Vol 556-557 ◽  
pp. 363-366 ◽  
Author(s):  
Jörg Pezoldt ◽  
Christian Förster ◽  
Volker Cimalla ◽  
Florentina Will ◽  
Ralf Stephan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Internal Stress ◽  
Thin Layers ◽  
Quality Factors ◽  
Resonant Frequencies ◽  
Suitable Technique

The resonant frequencies and quality factors of MEMS and NEMS depend critically on the layer quality and the residual stress in the SiC/Si heterostructure. It is demonstrated, that FTIRellipsometry is a suitable technique for monitoring the inhomogeneous residual stress inside SiC/Si heterostructures containing thin layers and their variation with during processing.

Dual-Band Bandpass Filter Optimized for High Q-Factor

2021 ◽  
Vol 36 (4) ◽  
pp. 398-410
Author(s):  
Walid Fahmy ◽  
Asmaa Farahat ◽  
Khalid Hussein ◽  
Abd-El-Hadi Ammar
Keyword(s):  
Quality Factor ◽  
Bandpass Filter ◽  
High Quality Factor ◽  
Dual Band ◽  
Optimized Design ◽  
Hybrid Architecture ◽  
Quality Factors ◽  
High Quality ◽  
Resonant Frequencies ◽  
Simulation Results

High quality factor bandpass filters based on a number of cascaded resonators of dual-resonance mechanism are proposed in the present paper. Each resonator is constructed as two overlapped coplanar waveguide (CPW) resonant structures. The cascaded resonators mediate microwave coupling between two isolated corner-shaped CPW feeders only at the resonant frequencies leading to a bandpass filter of high quality factor. The two resonant frequencies and the separation between them can be fine-tuned by the dimensions of the structure. The effects of the dimensional parameters of the resonator and the feeding CPW regions on the resonant frequencies and the performance of the bandpass filter are investigated. The effect of the loss tangent of the dielectric substrate material on the quality factors at the two resonant frequencies is studied. Three prototypes of the proposed filter are fabricated and experimentally studied for more understanding of the underlying physical principles of operation and for verifying some of the simulation results. The experimental results show good agreement when compared with the corresponding simulation results. It is shown that, at low enough absolute temperature, the proposed structure can operate as superconducting microwave resonator when made from the appropriate materials. Also, it is shown that an optimized design of the proposed bandpass filter, based on superconducting CPWR structure, can achieve quality factors high enough to form a quantum data bus for hybrid architecture of quantum information systems.

Performance Modification of SiC MEMS

2009 ◽  
Vol 615-617 ◽  
pp. 621-624 ◽  
Author(s):  
Florentina Niebelschütz ◽  
Klemens Brueckner ◽  
Volker Cimalla ◽  
Matthias A. Hein ◽  
Jörg Pezoldt
Keyword(s):  
Residual Stress ◽  
Resonant Frequency ◽  
Epitaxial Growth ◽  
Quality Factor ◽  
Growth Conditions ◽  
Mems Devices ◽  
Quality Factors ◽  
Resonant Frequencies ◽  
Raman Analysis

The adjustment of the properties of 3C-SiC based MEMS devices, i.e. the quality factor and resonant frequency, was achieved by changing the residual stress and the 3C-SiC material quality of the SiC-layers grown on Si(111) by manipulating the nucleation conditions and growth conditions with Ge deposition prior to the carbonization and epitaxial growth. Previous Raman analysis of the SiC-layers and measured resonant frequencies and quality factors of the processed MEMS show a dependence on the Ge amount at the interface of the Si/SiC heterostructure, which allows to adjust the MEMS properties to the requirements needed for certain applications.

Quality Factors of Crystalline Semiconductor Nanocomposite Resonators

2011 ◽  
Author(s):  
Puroorava Chakravarthy ◽  
Gang Li
Keyword(s):  
Molecular Dynamics ◽  
Energy Dissipation ◽  
Quality Factor ◽  
Material Properties ◽  
Quality Factors ◽  
Key Factors ◽  
Nano Scale ◽  
Crystalline Semiconductor ◽  
Bulk Matrix ◽  
Semiconductor Nanocomposite

A nanocomposite can generally be regarded as a solid combining a bulk matrix and nano-scale phases. The phases can be nanoparticles, nanowires, nanoplatelets and etc. The addition of nanosized phases into the bulk matrix can lead to significantly different material properties compared to their macrocomposite counterparts. In this work, we investigate the characteristics of energy dissipation in nanocomposite resonators. By using classical molecular dynamics (MD), we calculate the quality factors of layered and fibrous crystalline semiconductor nanocomposite resonators. Key factors that determine the quality factor of the nanocomposite resonators are identified and analyzed.

Application of bandlimited anelastic models to wave propagation in highly attenuative media

1995 ◽  
Vol 85 (5) ◽  
pp. 1359-1372
Author(s):  
Hsi-Ping Liu
Keyword(s):  
Wave Propagation ◽  
Quality Factor ◽  
Lower Limit ◽  
Relaxation Function ◽  
Function Approach ◽  
Creep Function ◽  
Frequency Range ◽  
Quality Factors ◽  
Low Frequencies ◽  
Near Surface

Abstract Because of its simple form, a bandlimited, four-parameter anelastic model that yields nearly constant midband Q for low-loss materials is often used for calculating synthetic seismograms. The four parameters used in the literature to characterize anelastic behavior are τ1, τ2, Qm, and MR in the relaxation-function approach (s1 = 1/τ1 and s2 = 1/τ2 are angular frequencies defining the bandwidth, MR is the relaxed modulus, and Qm is approximately the midband quality factor when Qm ≫ 1); or τ1, τ2, Qm, and MR in the creep-function approach (s1 = 1/τ1 and s2 = 1/τ2 are angular frequencies defining the bandwidth, and Qm is approximately the midband quality factor when Qm ≫ 1). In practice, it is often the case that, for a particular medium, the quality factor Q(ω0) and phase velocity c(ω0) at an angular frequency ω0 (s1 < ω0 < s2; s1 < ω0 < s2) are known from field measurements. If values are assigned to τ1 and τ2 (τ2 < τ1), or to τ1 and τ2 (τ2 < τ1), then the two remaining parameters, Qm and MR, or Qm and MR, can be obtained from Q(ω0). However, for highly attenuative media, e.g., Q(ω0) ≦ 5, Q(ω) can become highly skewed and negative at low frequencies (for the relaxation-function approach) or at high frequencies (for the creep-function approach) if this procedure is followed. A negative Q(ω) is unacceptable because it implies an increase in energy for waves propagating in a homogeneous and attenuative medium. This article shows that given (τ1, τ2, ω0) or (τ1, τ2, ω0), a lower limit of Q(ω0) exists for a bandlimited, four-parameter anelastic model. In the relaxation-function approach, the minimum permissible Q(ω0) is given by ln [(1 + ω20τ21)/(1 + ω20τ22)]/{2 arctan [ω0(τ1 − τ2)/(1 + ω20τ1τ2)]}. In the creep-function approach, the minimum permissible Q(ω0) is given by {2 ln (τ1/τ2) − ln [(1 + ω20τ21)/(1 + ω20τ22)]}/{2 arctan [ω0(τ1 − τ2)/(1 + ω20τ1τ2)]}. The more general statement that, for a given set of relaxation mechanisms, a lower limit exists for Q(ω0) is also shown to hold. Because a nearly constant midband Q cannot be achieved for highly attenuative media using a four-parameter anelastic model, a bandlimited, six-parameter anelastic model that yields a nearly constant midband Q for such media is devised; an expression for the minimum permissible Q(ω0) is given. Six-parameter anelastic models with quality factors Q ∼ 5 and Q ∼ 16, constant to 6% over the frequency range 0.5 to 200 Hz, illustrate this result. In conformity with field observations that Q(ω) for near-surface earth materials is approximately constant over a wide frequency range, the bandlimited, six-parameter anelastic models are suitable for modeling wave propagation in highly attenuative media for bandlimited time functions in engineering and exploration seismology.

RESEARCH OF METHODS FOR DECREASE OF THE CAPACITANCE RATIO IN THE STW-RESONATORS

2021 ◽  
pp. 43-56
Author(s):  
S. A. Dobershtein ◽  
N. M. Zhilin ◽  
I. V. Veremeev
Keyword(s):  
Experimental Data ◽  
Quality Factor ◽  
Quality Factors ◽  
Topology Change ◽  
Series Connection ◽  
Capacitance Ratio ◽  
And Topology

This paper presents the research of methods for decrease of the capacitance ratio in the STW-resonators without significant degradation of the quality factor by use of the external inductors and topology change: IDT division on parts and their series connection. The calculated and experimental data are presented for 416 MHz and 766 MHz STW-resonators with quality factors Q = 7000–7978. The capacitance ratio has been reduced from 1200 to 301.

Rational Design of Organic Electro-Optic Materials

2001 ◽  
Vol 708 ◽  
Author(s):  
Alex Jen ◽  
Robert Neilsen ◽  
Bruce Robinson ◽  
William H. Steier ◽  
Larry Dalton
Keyword(s):  
Wavelength Division Multiplexing ◽  
Material Properties ◽  
Electrostatic Interactions ◽  
Rational Design ◽  
Elevated Temperatures ◽  
Optical Loss ◽  
Quality Factors ◽  
Electro Optic ◽  
Lattice Hardening

ABSTRACTA number of material properties must be optimized before organic electro-optic materials can be used for practical device applications. These include electro-optic activity, optical transparency, and stability including both thermal and photochemical stability. Exploiting an improved understanding of the structure/function relationships, we have recently prepared materials exhibiting electro-optic coefficients of greater than 50 pm/V and optical loss values of less than 0.7 dB/cm at the telecommunication wavelengths of 1.3 and 1.55 microns. When oxygen is excluded to a reasonable extent, long-term photostability to optical power levels of 20 mW has been observed. Photostability is further improved by addition of scavengers and by lattice hardening. Long-term (greater than 1000 hours) thermal stability of poling-induced electro-optic activity is also observed at elevated temperatures (greater than 80°C) when appropriate lattice hardening is used. The successful improvement of organic electro-optic materials rests upon (1) attention to the design of chromophore structure including design to inhibit unwanted intermolecular electrostatic interactions and to improve chromophore instability and (2) attention to processing conditions including those involved in spin casting, electric field poling, and lattice hardening. A particularly attractive new direction has been the exploitation of dendrimer structures and particularly of multi-chromophore containing dendrimer structures. This approach has permitted the simultaneous improvement of all material properties. Development of new materials has facilitated the fabrication of a number of prototype devices and most recently has permitted investigation of the incorporation of electro-optic materials into photonic bandgap and microresonator structures. The latter are relevant to active wavelength division multiplexing (WDM). Significant quality factors (greater than 10,000) have been realized for such devices permitting wavelength discrimination at telecommunication wavelengths of 0.01 nm.

scholarly journals Analysis Of Usability In FIFA 15 and Pro Evolution Soccer (PES) 15 Using Mc Call’s Quality Factors

2016 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Yudistira Yudistira ◽  
Ahmad Subhan Yazid ◽  
Agung Fatwanto
Keyword(s):  
Quality Factor ◽  
Software Quality ◽  
Usability Testing ◽  
Quality Factors ◽  
User Interest ◽  
And Training ◽  
Better Than

FIFA 15 and Pro Evolution Soccer (PES) 15 are soccer games that are popular in Indonesia. Usability testing needs to be done to assess user interest and satisfaction with both and provide an overview of the comparison of them. The framework used for testing is McCall’S. The test combines operability matrix and training matrix to determine software quality. McCall’S was chosen because it has a reliable and comprehensive quality factor indicators. The results of the tests carried out were data on the operability level of PES15 games of 76.81% ± 15.76% and FIFA15 games of 70.65% ± 20.73%. Testing of training matrices produced 15.96 ± 21.74 seconds for PES15 and 78.29 ± 25.73 seconds for FIFA15 game training matrix. The data shows that reusability of PES15 is better than FIFA15.

Research on Internal Stress in Electroplated Cu Films and Ni Films on Ag Substrates

2011 ◽  
Vol 287-290 ◽  
pp. 3085-3088
Author(s):  
Yao Min Zhu ◽  
Shan Shan Wang ◽  
Feng Zhang Ren
Keyword(s):  
Film Thickness ◽  
Internal Stress ◽  
Calculation Model ◽  
Internal Stresses ◽  
Film Material ◽  
Beam Test ◽  
Cu Films ◽  
Cu Film ◽  
Reduced Gradient

Electroplating was employed to prepare Cu films and Ni films on Ag substrates. The average internal stresses in Cu film and Ni film were measured in situ by cantilever beam test. The values of experimental internal stresses were compared with theoretical internal stresses. The results showed that the internal stresses of Cu film and Ni film decreased with the increase of the film thickness. The reduced gradient was faster. The values of experimental and theoretical internal stresses had the same variation trend with film thickness and the same characteristics (tensile stress). Theoretical calculation model of internal stress was of accuracy. The internal stress for the same substrate was in relation to the film material.

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