AFM( atomic force microscope) 原子力電子顯微鏡

1. AFM(atomic force microscope)原子力電子顯微鏡 Professor:Kuen-Hsien Wu Student:Syue-AnCeng

2. Outline • Introduction • Basic Principles • Application • Conclusion • References

3. Introduction Measurement needs in a vacuum. 需要在真空中測量 Samples must be conductive. 樣品必須導電 If it is not to be plated with a conductive gold or white gold. 若是不導電就必須鍍上金或者白金 Samples can not be a powder or a volatile items. 樣品不能是粉末或著揮發性的物品 「余憶童稚時，能張目對日，明察秋毫。 見藐小微物，必細察其紋理，故時有物外之趣。」 -沈復 Cork cell wall Robert Hooke

4. Introduction • After the 1930s, based on quantum mechanics, can grasp and describe the role between atoms. • 1930 年代之後，在量子力學的基礎上，能夠掌握並描述原子之間的作用 • For example, quantum tunneling effect and van der Waals force. • 例如量子穿隧效應和凡德瓦爾力。 STM , scanning tunneling microscopy

5. Introduction Atomic force microscopy measurements objects mainly van der Waals force, exists between all types of atom. 原子力顯微鏡量測對象的主要是凡德瓦爾力，存在於所有種類的原子之間 Gerd Binnig Calvin Quate Christoph Gerber AFM, atomic force microscopy

6. Basic Principles • The AFM consists of a cantilever with a sharp tip (probe) at its end that is used to scan the specimen surface. • AFM的關鍵組成部分是一個頭上帶有一個用來掃描樣品表面的尖細探針的微觀懸臂 • When the tip is brought into proximity of a sample surface, forces between the tip and the sample lead to a deflection of the cantilever according to Hooke’slaw. • 當探針被放置到樣品表面附近的地方時，懸臂上的探針頭會因為受到樣品表面的力而遵從虎克定律彎曲偏移。 • mechanical contact force, van der Waals forces, capillary forces, chemical bonding, electrostatic forces, magnetic forces (see magnetic force microscope, MFM), Casimir forces, solvation forces, etc • 機械接觸力、范德華力、毛吸力、化學鍵、取向力、靜電力、磁力（見磁力顯微鏡）卡西米爾效應力、溶劑力等等

7. Basic Principles • Typically, the deflection is measured using a laser spot reflected from the top surface of the cantilever into an array of photodiodes. Other methods that are used include optical interferometry, capacitive sensing or piezoresistiveAFM cantilevers. • 偏移會由射在微懸臂上的雷射束反射至光敏二極體陣列而測量到，較薄之懸臂表面常鍍上反光材質（ 如鋁）以增強其反射。其他方法還包括光學干涉法、電容法和壓電效應法。 • These cantilevers are fabricated with piezoresistive elements that act as a strain gauge. Using a Wheatstone bridge, strain in the AFM cantilever due to deflection can be measured, but this method is not as sensitive as laser deflection or interferometry. • 這些探頭通常由採用壓電效應的變形測量器而製得。通過惠斯登電橋，探頭的形變可以被測得，不過這種方法沒有雷射反射法或干涉法靈敏。

8. Basic Principles • Imaging modes • Tapping mode • 輕敲模式 • Contact mode • 接觸模式 • Non-contact mode • 非接觸模式

9. Basic Principles • Tapping mode

10. Basic Principles • Contact mode

11. Basic Principles • Non-contact mode Van der Waals forces

12. Application • Measuring surface height • 測量表面高低 • Measuring the electrostatic force, magnetic force • 測量靜電力、磁力 • Nanolithography • 奈米蝕刻 KPFM ,Kelvin probe force microscope 克爾文力顯微鏡 EFM ,Electrostatic force microscopy 靜電力顯微鏡

13. 系統規格及型號： • 機型：NT-MDT Solver P47 （SP-47） • 成像模式：原子力顯微鏡（AFM）及掃描電流顯微鏡（C-AFM） • 掃描面積：40 X 40 μm2 • 試片尺寸：最大1.5 × 2 cm2 • 最大高度掃描範圍：~ 5 μm • 解析度：XY平面2 nm，Z軸0.07 nm • 操作環境：大氣1atm • 探針規格： • (a) NanosensorsPointProbePlus-RT-NCHR，tip curvature radius < 7nm • (b) NanosensorsSuperSharpSilicon-NCHR，tip curvature radius < 2nm • (c) μ-masch NSC15，tip curvature radius < 7nm C-AFM AFM

14. Conclusion • 原子力顯微鏡的技術仍在不停推進著，應用層面也在不停的推廣中，在未來將與生醫等技術領域緊密結合，因此可對原子力顯微鏡抱有相當程度的期待。

15. References • 國家實驗研究院-檢驗分析組-原子力顯微鏡 • 維基百科-關鍵字”Atomic force microscopy” • 初探原子力顯微鏡-陳佳伶

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