一種原子力顯微儀探針功率檢測電路之研發

The Study of the Power Detector Circuit for the Probe of Atomic Force Microscopes

林仁隆(Ren-Lung Lin)

指導教授 ： 黎文龍

國立臺北科技大學/機電學院/自動化科技研究所/碩士(2006年)

摘要

隨著奈米科技的進步，利用原子力顯微儀(AFM)做為主要的研究工具，來發現或驗證新的物理及化學現象，成為不可避免的趨勢，然而，對於 AFM 本身的製作開發，其周邊環境因素的控制（如振動、溫度、干擾雜訊等）、操作介面及訊號擷取後之處理，甚至探針的製作研究等，都是影響 AFM顯像品質的重要影響因子。基本上， AFM 是依據量測針尖與樣品之原子間的吸引力或排斥力的大小不同，達到的量測與顯像解析的目的，一般的探針大約可感測到 N 的力量大小，在如此微小的力量情況下，一個可靠有效的探針振盪懸臂樑之彈簧係數校正方法也就相形重要。如果校正程序不夠正確，其原子力顯微儀所呈現出的量測現象及數據是有待質疑的。
本文主要針對 AFM 探針消耗功率量測電路研究開發，經由此量測系統電路來針對探針振盪輸入源進行量測，特別是振盪源所提供的功率值，再根據能量不滅定理，進一步的推論得知探針本身所消耗的功率，同時地依據得知耗能的多少，未來只要藉著找出耗能與探針阻尼的關係，並利用阻尼與彈簧係數的關係式，即可獲得耗能與彈簧係數的關係，將可進而應用成為一種新的探針懸臂樑彈簧係數校準技術。在本文研發中，將著重於適用於探針功率檢測系統電路做設計上的研發，分析量測系統整體設計理念及轉換理論，藉由架構的探討中，利用電子電路設計技術，設計研發出一種 AFM 探針功率檢測電路。此電路優點在於可隨機性，操作介面簡單，穩定性高，並可準確的量測出探針振盪源所供給的的功率值。

關鍵字

原子力顯微儀 ； 探針彈簧係數校正 ； 耗能量測系統

並列摘要

With the advent of nano era, atomic force microscopes (AFM) have been widely adopted as the major tool for analyzing or discovering new phenomena in research labs. However, it is clear that the environmental conditions like vibrations, changes in temperatures, noises etc., as well as post signal processing, can always affect the images of an AFM. Basically, an AFM is using the attractive or expulsive force between the atoms of the AFM probe and the sample. The force can be as small as at the order of N, in which any minute deviation may be fatal to the measurement. In addition, the calibration of the cantilever probe stiffness that is used as the medium of the force measurement can be as important as the AFM itself.
The main object of the present research is to develop a power detecting circuit that can be applied to AFM for acquiring the power consumption during the oscillations of probes. Through the accurate power consumption measurement at the input, one is able to estimate the energy dissipated from the tip of the probe. By doing so, it is possible further to deduce that the relations between the probe stiffness and the energy input. As a consequence, an in situ and reliable stiffness calibration process can be established. The current report focuses mainly at the design and verification of power detecting circuits. Utilizing the modern electronic techniques and components, it has been found that such a simple and highly stable circuit design is possible.

並列關鍵字

AFM ； Probe stiffness calibration ； Power consumption circuits

參考文獻

[2] Ducker, W.A., R.F. Cook, and D.R. Clarke, Force measurement using an AC atomic force microscope. J. Appl. Phys. (USA), 1990. 67,(9, pt.1): pp. 4045-52.

[3] T. R. Albrecht, P. Grtitter, D. Horne, and D. Rugar, “Frequency modulation detection using highdkantilevers for enhanced force microscope sensitivity,” IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120.

[4] Kato., N., Kikuta, H., Naknno, T., Matsumoto, T., and Iwata, K., “System analysis of the force-feedback method for force curve measurements,” Review of Scientific Instruments, 70(5) , pp.2402-2407, 1999.

[5] Sader, J.E , Larson, I, Mulvancy, P. and White, L.R., Method for the calibration of atomic force microscope cantilevers, Review of Scientific Instruments, 66(7),pp.3789-3798, 1995.

[6] Gibson, C.T., Watson, G.S. and Myhra, S., Determination of the spring constants of probe for force microscopy/spectroscopy, Nanotechnology, 7, pp.259-262, 1996.