• Advances in nano research
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• v.5 no.4
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• pp.337-357
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• 2017

Knowledge of thin films mechanical properties is strongly associated to the reliability and the performances of Nano Electro Mechanical Systems (NEMS). In the literature, there are several methods for micro materials characterization. Bulge test is an established nondestructive technique for studying the mechanical properties of thin films. This study improve the performances of NEMS by investigating the mechanical behavior of Nano rectangular thin film (NRTF) made of new material embedded in Nano Electro Mechanical Systems (NEMS) by developing the bulge test technique. The NRTF built from adhesively-bonded layers of basalt fiber reinforced polymer (BFRP) laminate composite materials in Nano size at room temperature and were used for plane-strain bulging. The NRTF is first pre-stressed to ensure that is no initial deflection before applied the loads on NRTF and then clamped between two plates. A differential pressure is applying to a deformation of the laminated composite NRTF. This makes the plane-strain bulge test idea for studying the mechanical behavior of laminated composite NRTF in both the elastic and plastic regimes. An exact solution of governing equations for symmetric cross-ply BFRP laminated composite NRTF was established with taking in-to account the effect of the residual strength from pre-stressed loading. The stress-strain relationship of the BFRP laminated composite NRTF was determined by hydraulic bulging test. The NRTF thickness gradation in different points of hemisphere formed in bulge test was analysed.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.85-90
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• 2007

This paper presents the growth conditions and characteristics of polycrystalline 3C-SiC (silicon carbide) thin films for M/NEMS applications related to harsh environments. The growth of the 3C-SiC thin film on the oxided Si wafers was carried out by APCVD using HMDS (hexamethyildisilane: $Si_{2}(CH_{3})_{6})$ precursor. Each samples were analyzed by XRD (X-ray diffraction), FT-IR (fourier transformation infrared spectroscopy), RHEED (reflection high energy electron diffraction), GDS (glow discharge spectrometer), XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscope) and TEM (tunneling electro microscope). Moreover, the electrical properties of the grown 3C-SiC thin film were evaluated by Hall effect. From these results, the grown 3C-SiC thin film is very good crystalline quality, surface like mirror and low defect. Therefore, the 3C-SiC thin film is suitable for extreme environment, Bio and RF M/NEMS applications in conjunction with Si fabrication technology.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.361.1-361.1
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• 2016

Due to their high sensitivity, fast response, small energy consumption and ease of integration, nanoelectromechanical systems (NEMS) have attracted much interest in various applications such as high speed memory devices, energy harvesting devices, frequency tunable RF receivers, and ultra sensitive mass sensors. Since the device performance of NEMS is closely related with the mechanical and flexural properties of the material in NEMS, analysis of the mechanical and flexural properties such as intrinsic tensile stress and Young's modulus is a crucial factor for designing the NEMS structures. In the present work, the intrinsic mechanical properties of highly stressed silicon nitride (SiN) beams are investigated as a function of the beam length using two different techniques: (i) dynamic flexural measurement using optical interferometry and (ii) quasi-static flexural measurement using atomic force microscopy. The reliability of the results is analysed by comparing the results from the two different measurement techniques. In addition, the mass density, Young's modulus and internal stress of the SiN beams are estimated by combining the techniques, and the prospect of SiN based NEMS for application in high sensitive mass sensors is discussed.

• Tribology and Lubricants
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• v.24 no.2
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• pp.63-71
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• 2008

Friction and adhesion tests were conducted to investigate tribological characteristics of materials for MEMS/NEMS using atomic force microscope (AFM). AFM Si tips were chemically modified with a self-assembled monolayer (SAM) derived from trichlorosilane like octadecyltrichlorosilane (OTS) and (1H, 1H, 2H, 2H-perfluorooctyl) trichlorosilane (FOTS), and various materials, such as Si, Al, Au, Cu, Ti and PMMA films, were prepared for the tests. SAMs were coated on Si wafer by dipping method prior to AFM tip to determine a proper dipping time. The proper dipping time was determined from the measurements of contact angle, surface energy and thickness of the SAMs. AFM tips were then coated with SAMs by using the same coating condition. Friction and adhesion forces between the AFM Si tip modified with SAM and MEMS/NEMS materials were measured. These forces were compared to those when AFM tip was uncoated. According to the results, after coating OTS and FOTS, the friction and adhesion forces on all materials used in the tests decreased; however, the effect of SAM on the reduction of friction and adhesion forces could be changed according to counterpart materials. OTS was the most effective to reduce the friction and adhesion forces when counterpart material was Cu film. In case of FOTS, friction and adhesion forces decreased the most effectively on Au films.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.6
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• pp.939-946
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• 2018

In this work, we present simple schematics for a three-terminal graphene-based nanoelectromechanical switch with the vertical electrode, and we investigated their operational dynamics via classical molecular dynamics simulations. The main structure is both the vertical pin electrode grown in the center of the square hole and the graphene covering on the hole. The potential difference between the bottom gate of the hole and the graphene of the top cover is applied to deflect the graphene. By performing classical molecular dynamic simulations, we investigate the nanoelectromechanical properties of a three-terminal graphene-based nanoelectromechanical switch with vertical pin electrode, which can be switched by the externally applied force. The elastostatic energy of the deflected graphene is also very important factor to analyze the three-terminal graphene-based nanoelectromechanical switch. This simulation work explicitly demonstrated that such devices are applicable to nanoscale sensors and quantum computing, as well as ultra-fast-response switching devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.99.2-99.2
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• 2016

본 발표에서는 공중에 떠있는 그래핀 기반 나노전기역학 시스템 (NEMS)의 기본 물성과 응용 방법에 대해 소개하고자 한다. 단겹 그래핀을 리본형태로 패턴하고 마이크로 전사기술을 통해 공중에 띄우는 공정을 이용한 그래핀 NEMS 소자 제작 방법을 먼저 소개하고 우리 연구그룹에서 지금까지 측정한 이 구조의 기본 역학적 물성 연구 결과를 소개한다. 미세 질량이 공중에 매달린 그래핀에 더해짐에 따라 역학적 공명 주파수가 줄어드는 현상을 이용하여 그래핀 기반 초미세 질량 센서 응용 방법에 대해 먼저 말하고 이후 같은 구조로 역학적 공명주파수를 이용한 RF 소자 응용 가능성에 대해서 이야기 하고자 한다. 마지막으로 다시 같은 구조를 통해 그래핀 자체에서 강한 가시광선이 발광되는 현상을 처음으로 발견한 내용에 대해 소개하고 이 현상에 대한 물리적 분석과 함께 응용 가능성을 제안하며 발표를 마무리하고자 한다.

• Journal of Mechanical Science and Technology
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• v.19 no.9
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• pp.1711-1719
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• 2005

In an electro statically actuated nanoelectromechanical system (NEMS) resonator, it is shown that both the resonance frequency and the resonance quality (Q) factor can be manipulated. How much the frequency and quality factor can be tuned by excitation voltage and resistance on a doubly-clamped beam resonator is addressed. A mathematical model for investigating the tuning effects is presented. All results are shown based on the feasible dimension of the nanoresonator and appropriate external driving voltage, yielding up to 20 MHz resonance frequency. Such parameter tuning could prove to be a very convenient scheme to actively control the response of NEMS for a variety of applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.18-19
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• 2008

Polycrystalline(poly) 3C-SiC film is a promising structural material for M/NEMS used in harsh environments, bio and fields. In order to realize poly 3C-SiC based M/NEMS devices, the electrical properties of poly 3C-SiC film have to be optimized. The n-type poly 3C-SiC thin film is deposited by APCVD using HMDS$(Si_2(CH_3)_6)$ as single precursor and are in-situ doped using N2. Resistivity values as low as 0.014 $\Omega$cm were achieved. The carrier concentration increased with doping from $3.0819\times10^{17}$ to $2.2994\times10^{19}cm^{-3}$ and electronicmobility increased from 2.433 to 29.299 $cm^2/V{\cdot}s$.

• Advances in nano research
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• v.16 no.2
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• pp.201-215
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• 2024

The present research study emphasizes the utilization of mathematical simulation on a nanoelectromechanical systems (NEMS) sensor to facilitate the detection of injuries in players and equipment. Specifically, an investigation is conducted on the thermal buckling behavior of a small-scale truncated conical, cylindrical beam, which is fabricated using porous functionally graded (FG) material. The beam exhibits non-uniform characteristics in terms of porosity, thickness, and material distribution along both radial and axial directions. To assess the thermal buckling performance under various environmental heat conditions, classical and first-order nonlocal beam theories are employed. The governing equations for thermal stability are derived through the application of the energy technique and subsequently numerically solved using the extended differential quadratic technique (GDQM). The obtained results are comprehensively analyzed, taking into account the diverse range of effective parameters employed in this meticulous study.

• KIPE Magazine
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• v.14 no.1
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• pp.26-33
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• 2009

광대역 반도체중에서도 SiC(Silicon Carbide)는 우수한 전기적, 기계적, 열적, 화학적, 광학적 그리고 생체 적합성 등으로 인하여 지난 반세기 동안 급속히 발전하고 있는 SiM/NEMS(Micro/Nano Electro Mechanical System)를 대처할 수 있는 차세대 M/NEMS로써 고온, 고압, 고진동, 고습도 등의 극한 환경에서도 사용 가능한 자동차, 선박, 우주항공, 산업 프랜트용 마이크로 센서 및 액츄에이터, 초고주파수 정보통신용 부품 그리고 바이오 센서 등의 분야에 크게 주목을 받고 있다. 본 논문에서는 현재 SiC M/NEMS의 연구개발 현황에 대해서 소개하고자 한다.