Various multilayered thin films are extensively used as the basic component of some micro-electro-mechanical systems, requiring an efficient measurement method for material parameters, such as Young’s modulus, residual stress, etc. This paper developed a novel measurement method to extract the Young’s moduli and residual stresses for individual layers in multilayered thin films, based on the first resonance frequency measurements of both cantilever beams and doubly-clamped beams. The fabrication process of the test structure, the corresponding modeling and the material parameter extraction process are introduced. To verify this method, the test structures with gold/polysilicon bilayer beams are fabricated and tested. The obtained Young’s moduli of polysilicon films are from 151.38 GPa to 154.93 GPa, and the obtained Young’s moduli of gold films are from 70.72 GPa to 75.34 GPa. The obtained residual stresses of polysilicon films are from −14.86 MPa to −13.11 MPa (compressive stress), and the obtained residual stresses of gold films are from 16.27 to 23.95 MPa (tensile stress). The extracted parameters are within the reasonable ranges, compared with the available results or the results obtained by other test methods.

Based on the first resonance frequency measurement of multilayer beams, a simple extraction method has been developed to extract the Young's modulus of individual layers. To verify this method, the double-layer cantilever, as a typical example, is analyzed to simplify the situation and finite element modeling (FEM) is used in consideration of the buckling and unbuckling situation of cantilevers. The first resonance frequencies, which are obtained by ANSYS (15.0, ANSYS Inc., Pittsburgh, PA, USA) with a group of thirteen setting values of Young's modulus in the polysilicon layer are brought into the theoretical formulas to obtain a new group of Young's modulus in the polysilicon layer. The reliability and feasibility of the theoretical method are confirmed, according to the slight differences between the setting values and the results of the theoretical model. In the experiment, a series of polysilicon-metal double-layer cantilevers were fabricated. Digital holographic microscopy (DHM) (Lyncée Tech, Lausanne, Switzerland) is used to distinguish the buckled from the unbuckled. A scanning laser Doppler vibrometer (LDV) (Polytech GmbH, Berlin, Germany) system is used to measure the first resonance frequencies of them. After applying the measurement results into the theoretical modulus, the average values of Young's modulus in the polysilicon and gold layers are 151.78 GPa and 75.72 GPa, respectively. The extracted parameters are all within the rational ranges, compared with the available results.

This paper presents an intuitive yet effective in-situ thermal diffusivity testing structure and testing method. The structure consists of two doubly clamped beams with the same width and thickness but different lengths. When the electric current is applied through two terminals of one beam, the beam serves as thermal resistor and the resistance R(t) varies as temperature rises. A delicate thermodynamic model considering thermal convection, thermal radiation, and film-to-substrate heat conduction was established for the testing structure. The presented in-situ thermal diffusivity testing structure can be fabricated by various commonly used micro electro mechanical systems (MEMS) fabrication methods, i.e., it requires no extra customized processes yet provides electrical input and output interfaces for in-situ testing. Meanwhile, the testing environment and equipment had no stringent restriction, measurements were carried out at normal temperatures and pressures, and the results are relatively accurate.

Multilayered structures are increasingly used in MEMS. Based on the resonant frequency of the doubly-clamped multilayered beam, the Young's modulus and residual stress for an individual layer have been measured by designing beam test structures for each layer with different widths. Taking into account the buckling or no buckling problem of the multilayered beam, this paper introduces a model for the resonant frequency of the beam. An approach to extract the Young's modulus and residual stress for the individual layer is developed. The validity of this approach has been studied using finite element modeling. As a multilayered example, test structures for a gold/polysilicon bilayer beam were fabricated. A scanning laser Doppler vibrometer system was used to measure the resonant frequency of the beam. The extracted parameters are that the average value of Young's modulus of polysilicon and gold are 133.7 GPa and 78.6 GPa with standard deviation being 4.2 GPa and 11.5 GPa, respectively; the average value of residual stress of polysilicon and gold are 13.9 MPa (compressive) and 19.7 MPa (tensile) with standard deviation being 0.47 MPa and 4.4 MPa, respectively.

Young’s modulus of a silicon nanobeam with a rectangular cross-section is studied by molecular dynamics method. Dynamic simulations are performed for doubly clamped silicon nanobeams with lengths ranging from 4.888 to 12.491 nm and cros-sections ranging from 1.22 nm × 1.22 nm to 3.39 nm × 3.39 nm. The results show that Young’s moduli of such small silicon nanobeams are much higher than the value of Young’s modulus for bulk silicon. Moreover, the resonant frequency and Young’s modulus of the Si nanobeam are strongly dependent not only on the size of the nanobeam but also on surface effects. Young’s modulus increases significantly with the decreasing of the thickness of the silicon nanobeam. This result qualitatively agrees with one of the conclusions based on a semicontinuum model, in which the surface relaxation and the surface tension were taken into consideration. The impacts of the surface reconstruction with (2 × 1) dimmers on the resonant frequency and Young’s modulus are studied in this paper too. It is shown that the surface reconstruction makes the silicon nanobeam stiffer than the one without the surface reconstruction, resulting in a higher resonant frequency and a larger Young’s modulus.

In this paper, a direct and simple method to characterize the elastic modulus of individual layers for composite films by in situ measuring of MEMS test structures is presented. The structure is composed of a set of microactuators which contains a rigid plate with two supporting composite beams. A model is developed to describe analytically the relationship between the force and the deflection of microactuators by electrostatic measurements, and the elastic modulus of multi-layered beams with different widths are evaluated. FEM simulations are implemented to validate the accuracy of the relationship between the on-load voltage and the capacitance between the microactuator and the electrode on the substrate. Test structures are fabricated using CMOS-MEMS process and experiments are to be carried out soon.

This paper presents a direct and simple method to characterize the elastic modulus and residual stress of individual layers for composite films by measuring the resonant frequency. The structure is composed of the composite fixed-fixed beam. A model is developed to describe analytically elastic modulus and residual stress as a function of the resonant frequency of multi-layered fixed-fixed beams with different lengths and widths. FEM simulations are firstly implemented to validate the accuracy of the relationship between resonant frequency and mechanical properties. Experiments are then carried out by measuring the fundamental frequencies of the bilayer fixed-fixed beams with different lengths to extract the materials' properties.

The vibration behavior of doubly clamped silicon nanowires with square cross sections is studied by molecular dynamics method. Silicon nanowires have lengths ranging from 4.888 to 12.491 nm and cross sections ranging from 1.22 nm × 1.22 nm to 3.39 nm × 3.39 nm. The size dependence of the resonant frequency is studied in detail. The results show that the vibration behavior of Si nanowire is quite different from the macroscopic beam, and the resonant frequency is much higher than the result based on the continuum theory, but close to the theoretical result based on the semicontinuum approach. Surface reconstruction can strongly affect on vibration behavior. These results demonstrate that the classic theory may not be suitable for analysis of performances of nanostructures, and the conclusion of the study has a certain practical significance on related fields.

In this paper, via molecular dynamics simulations, employing aforementioned mechanism, we presented a conceptual design of nanoballista based on CNTs which contained a fullerene. All simulations were carried out in an NVT-ensemble and the Nose method was utilized to control the temperature. The interatomic interactions were described by the COMPSS force field.

In this work, a careful study on the electronic properties of 6-ZGNR with Pt doping at different sites using density functional theory, implemented in the CASTEP code was reported. Five different substitutional sites from the center to the edge of the 6-ZGNR were considered. The computational result indicates the antiferromagnetic (AFM) state is the most favorable for all the structures. So the band structure and spin density of the AFM ground state were presented.