• Title, Summary, Keyword: cantilevers

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Optimization of Fused Quartz Cantilever DRIE Process and Study on Q-factors (비정질 수정 캔틸레버의 식각 공정 최적화 및 Q-factor 연구)

  • Song, Eun-Seok;Kim, Yong-Kweon;Baek, Chang-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.2
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    • pp.362-369
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    • 2011
  • In this paper, optimal deep reactive ion etching (DRIE) process conditions for fused quartz were experimentally determined by Taguchi method, and fused quartz-based micro cantilevers were fabricated. In addition, comparative study on Q-factors of fused quartz and silicon micro cantilevers was performed. Using a silicon layer as an etch mask for fused quartz DRIE process, different 9 flow rate conditions of $C_4F_8$, $O_2$ and He gases were tested and the optimum combination of these factors was estimated. Micro cantilevers based on fused quartz were fabricated from this optimal DRIE condition. Through conventional silicon DRIE process, single-crystalline silicon micro cantilevers whose dimensions were similar to those of quartz cantilevers were also fabricated. Mechanical Q-factors were calculated to compare intrinsic damping properties of those two materials. Resonant frequencies and Q-factors were measured for the cantilevers having fixed widths and thicknesses and different lengths. The Q-factors were in a range of 64,000 - 108,000 for fused quartz cantilevers and 31,000 - 35,000 for silicon cantilevers. The experimental results supported that fused quartz had a good intrinsic damping property compared to that of single crystalline silicon.

Performance Evaluation of Non-contact Atomic Force Microscopy Due to Vibration Characteristics of Cantilever (비접촉 원자간력 현미경의 탐침 외팔보 진동특성에 따른 성능 평가)

  • 박준기;권현규;홍성욱
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.263-268
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    • 2003
  • This paper presents a result of performance evaluation fur non-contact scanning probe microscopy with respect to the vibration characteristics of cantilevers with tips. One of the current issues of the scanning probe microscopy technology is to increase the measurement speed, which is closely tied with the dynamic characteristics of cantilevers. The primary concern in this research is to investigate the relation between the maximum possible speed of non-contact scanning probe microscopy and the dynamic characteristics of cantilevers. First, the finite element analysis is made fur the vibration characteristics of various cantilevers in use. The computed natural frequencies of the cantilevers are in good agreement with measured ones. Then, each cantilever is tested with topographic measurement for a standard sample with the scanning speed changed. The performances of cantilevers are analyzed along with the natural frequencies of cantilevers. Experiments are also performed to test the effects of how to attach cantilevers in the piezo-electric actuator. Finally, measurement sensitivity has been analyzed to enhance the performance of scanning probe microscopy.

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Vibration Characteristics and Performance of Cantilever for Non-contact Atomic Force Microscopy (비접촉 원자간력 현미경의 탐침 캔틸레버 진동 특성 및 측정 성능 평가)

  • 박준기;권현규;홍성욱
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.6
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    • pp.495-502
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    • 2004
  • This paper presents the vibration analysis and the performance evaluation of cantilevers with probing tips for non-contact scanning probe microscopy. One of the current issues of the scanning probe microscopy technology is to increase the measurement speed, which is closely tied with the dynamic characteristics of cantilevers. The primary concern in this research is to investigate the relation between the maximum possible speed of non-contact scanning probe microscopy and the dynamic characteristics of cantilevers. First, the finite element analysis is made for the vibration characteristics of various cantilevers in use. The computed natural frequencies of the cantilevers are in good agreement with measured ones. Then, each cantilever is tested with topographic measurement for a standard sample with the scanning speed changed. The performances of cantilevers are analyzed along with the natural frequencies of cantilevers. Experiments are also performed to test the effects of how to attach cantilevers in the piezo-electric actuator. Finally, measurement sensitivity has been analyzed to enhance the performance of scanning probe microscopy.

Inelastic distortional buckling of cantilevers

  • Lee, Dong-Sik;Bradford, Mark Andrew
    • Steel and Composite Structures
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    • v.3 no.1
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    • pp.1-12
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    • 2003
  • Cantilevers are unique statically determinate structural elements with respect to their mode of overall buckling, in that the tension flange is the critical flange under gravity loading, and is the flange that deflects greatest during overall buckling. While this phenomenon does not complicate the calculation of the lateral buckling load, either theoretically or in structural design codes, it has been shown in previous research that the influence of distortion in the elastic buckling of cantilevers is not the same as that experienced in the elastic buckling of simply supported beams. This paper extends the study of the distortional buckling of cantilevers into the hitherto unconsidered inelastic range of structural response. A finite element method for studying the inelastic bifurcative instability of members whose cross-sections may distort during buckling is described, and the efficacy of the method is demonstrated. It is then used to study the inelastic distortional buckling of hot-rolled I-section cantilevers with two common patterns of residual stresses, and which may be restrained elastically from buckling by other structural elements.

A comparative study on Q-factors of fused quartz and silicon micro cantilevers (비정질 수정과 실리콘 마이크로 캔틸레버 구조물의 Q-factor 비교 연구)

  • Song, Eun-Seok;Kim, Yong-Kweon;Baek, Chang-Wook
    • Proceedings of the KIEE Conference
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    • pp.1505_1506
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    • 2009
  • In this paper, micro cantilevers which are made of two different materials - fused quartz and single crystalline silicon - and have similar dimensions were fabricated and their mechanical Q-factors were evaluated to compare intrinsic damping properties of those two materials. Resonant frequencies and Q-factors were measured for the cantilevers having fixed widths and thicknesses, and different lengths. The measured Q-values are in a range of 64,000 - 108,000 for fused quartz cantilevers, and 31,000 - 35,000 for silicon cantilevers, respectively. Experimental results support high Q-factors of fused quartz compared to single crystalline silicon due to its good intrinsic damping properties.

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Concrete arch bridges built by lattice cantilevers

  • Granata, Michele Fabio;Margiotta, Piercarlo;Recupero, Antonino;Arici, Marcello
    • Structural Engineering and Mechanics
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    • v.45 no.5
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    • pp.703-722
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    • 2013
  • In this paper a study about concrete arch bridges built by lattice cantilevers is presented. Lattice cantilevers are partial structures composed of deck, arch, piers and provisional steel diagonals, organized as reticular cantilever girders, in order to build arch bridges without the use of centrings, supports or temporary towers. Characteristics of this construction methodology with its variants are explained together with their implications in the erection sequence. Partial elastic scheme method is implemented in order to find initial forces of temporary cables and a forward analysis is carried out to follow the actual sequence of construction, by extending a procedure already applied to concrete cable-stayed bridges and to arches built by the classical suspended cantilever method. A numerical application on a case-study of a concrete arch bridge is performed together with a comparison between different methodologies followed for its construction sequence. Differences between erection by lattice cantilevers and cable-stayed cantilevers, are discussed. Results can be useful for designers in conceptual design of concrete arch bridges.

Fabrication of a Micro Actuator with p$^+$ Si Cantilevers for Optical Devices (p$^+$ Si 외팔보 구조를 이용한 광학 소자용 마이크로 구동기의 제작)

  • Park, Tae-Gyu;Yang, Sang-Sik
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.5
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    • pp.249-252
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    • 2001
  • The paper represents the design and fabrication of an electrostatic micro actuator with $p^+$,/TEX> Si cantilevers. The micro actuator consists of a plate suspended by four $p^+$,/TEX> silicon cantilevers and an electrode on a glass substrate. The $p^+$,/TEX> Si structure is fabricated by the boron diffusion process and the anisotropic wet etch process. The cantilevers of the micro actuator curl down because of the residual stress gradient in $p^+$,/TEX> silicon. When the electrostatic forec is applied to the $p^+$,/TEX> cantilevers, the vertical displacement of the plate can be achieved. The deflection of the cantilever due to the residual stress gradient and the vertical displacement by electrostatic force were calculated. The displacement of the plate was measured with a laser displacement meter for various input voltages and frequencies. The feasibility of the proposed micro actuator for the applications to optical pickup devices or optical communication devices was confirmed by the experiments.

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Thermo-piezoelectric $Si_3N_4$ cantilever array on a CMOS circuit for probe-based data storage using wafer-level transfer method (웨이퍼 본딩을 이용한 탐침형 정보 저장장치용 압전 켄틸레버 어레이)

  • Kim Young-Sik;Jang Seong-Soo;Lee Caroline Sun-Young;Jin Won-Hyeog;Cho Il-Joo;Nam Hyo-Jin;Bu Jong-Uk
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.2
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    • pp.96-99
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    • 2006
  • In this research, a wafer-level transfer method of cantilever away on a conventional CMOS circuit has been developed for high density probe-based data storage. The transferred cantilevers were silicon nitride ($Si_3N_4$) cantilevers integrated with poly silicon heaters and piezoelectric sensors, called thermo-piezoelectric $Si_3N_4$ cantilevers. In this process, we did not use a SOI wafer but a conventional p-type wafer for the fabrication of the thermo-piezoelectric $Si_3N_4$ cantilever arrays. Furthermore, we have developed a very simple transfer process, requiring only one step of cantilever transfer process for the integration of the CMOS wafer and cantilevers. Using this process, we have fabricated a single thermo-piezoelectric $Si_3N_4$ cantilever, and recorded 65nm data bits on a PMMA film and confirmed a charge signal at 5nm of cantilever deflection. And we have successfully applied this method to transfer 34 by 34 thermo-piezoelectric $Si_3N_4$ cantilever arrays on a CMOS wafer. We obtained reading signals from one of the cantilevers.

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Thermo-piezoelectric $Si_3N_4$ cantilever array on n CMOS circuit for probe-based data storage using wafer-level transfer method (웨이퍼 본딩을 이용한 탐침형 정보 저장장치용 열-압전 켄틸레버 어레이)

  • Kim Young-Sik;Nam Hyo-Jin;Lee Caroline Sunyoung;Jin Won-Hyeog;Jang Seong.Soo;Cho Il-Joo;Bu Jong Uk
    • 정보저장시스템학회:학술대회논문집
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    • pp.22-25
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    • 2005
  • In this research, a wafar-level transfer method of cantilever array on a conventional CMOS circuit has been developed for high density probe-based data storage. The transferred cantilevers were silicon nitride ($Si_3N_4$) cantilevers integrated with poly silicon heaters and piezoelectric sensors, called thermo-piezoelectric $Si_3N_4$ cantilevers. In this process, we did not use a SOI wafer but a conventional p-type wafer for the fabrication of the thermo-piezoelectric $Si_3N_4$ cantilever arrays. Furthermore, we have developed a very simple transfer process, requiring only one step of cantilever transfer process for the integration of the CMOS wafer and cantilevers. Using this process, we have fabricated a single thermo-piezoelectric $Si_3N_4$ cantilever, and recorded 65nm data bits on a PMMA film and confirmed a charge signal at 5nm of cantilever deflection. And we have successfully applied this method to transfer 34 by 34 thermo-piezoelectric $Si_3N_4$ cantilever arrays on a CMOS wafer. We obtained reading signals from one of the cantilevers.

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Fabrication of a Micro actuator with p+ Si cantilevers for Optical Devices (p+ Si 외팔보 구조를 이용한 광학 소자용 마이크로 구동기)

  • Park, Tae-Gyu;Yang, Sang-Sik
    • Proceedings of the KIEE Conference
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    • pp.2236-2238
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    • 2000
  • The paper represents the fabrication of an electrostatic micro actuator for optical devices. The micro actuator consists of a plate suspended four p+ silicon cantilevers and an electrode on a glass substrate. The cantilever curls down because of the residual stress gradient in p+ silicon. When input voltage is applied between the p+ cantilevers and the electrode. the cantilevers are pulled toward the electrode by the electrostatic force. The displacement of the plate is measured with a laser displacement meter for various input voltage and frequencies.

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