表面電位顯微鏡 (Kelvin Probe Force Microscopy, KPFM) 用於量測奈米尺度下樣品的功函數和表面電位分布，發展以來已經被廣泛應用於半導體、氧化物材料、光電元件及生物分子的分析、電子轉移等方面。其中振幅調制模式 (Amplitude Modulation，以下簡稱AM-KPFM) 的成像解析度會受到探針本身的雜散電容效應 (Stray Capacitance Effect) 所限制，此效應主要來自量測時，探針懸臂樑與樣品之間產生的長程靜電作用力，造成量測到的接觸電位差並非僅來自探針針尖與樣品的反應，而是包含其他部分共同產生的雜散電容，導致所得空間解析度下降以及量測到的樣品表面電位分布變廣。隨著半導體及光電元件尺寸日漸縮小且複雜化，此現象將會造成以AM-KPFM進行奈米尺度的電性成像面臨困難，使其對於異質材料的奈米電性分析失去適用性。

本研究以傳統微機電製程，導入特殊的針頭開孔技術來開發導電AFM同軸探針，進行批量化制備以降低成本，透過同軸的結構將懸臂樑與針頭錐體進行絕緣，減少量測中的雜散電容效應，提升AM-KPFM的空間解析度。並結合有限元素分析法模擬探針的彈性係數及共振頻率，經由光罩設計製作四種不同幾何形狀的探針，探討不同的懸臂樑機械性質對量測造成的影響。製程方面，於懸臂樑及探針針頭蝕刻進行參數優化，改善懸臂樑的粗糙度和輪廓變形的問題，並採取兩階段蝕刻針頭來得到較高的針尖。另一方面，吾人使用雷射共焦顯微鏡 (3D LM) 輔助針頭開孔判斷，3D LM係利用雷射光照射樣品的反射特性生成明暗對比，得到樣品的三維影像。透過調整光阻厚度後提高製程良率，針頭開孔率可達八成以上。

同軸探針測試使用Electric-Tune的方法來針對雜散電容效應進行量化分析，結果顯示具有相近彈性係數的探針，透過同軸結構的設計，能有效降低雜散電容效應，減少29-58 % 的懸臂樑與樣品之間之靜電作用力，使AM-KPFM量測電位差的空間解析度由1.4 µm 提升至780 nm。而k值較小的探針，藉由同軸結構的改良，可改善雜散電容效應，使其靈敏度與空間解析度與一般用於KPFM之商用探針相當，有利於應用在軟性材料之電性分析，減少對於樣品的損傷。除此之外，比較四種同軸探針對量測的影響發現，藉由優化懸臂樑性質和改變懸臂樑設計來提高Q值，可進一步提升AM-KPFM量測的靈敏度。

Amplitude Modulation Kelvin probe force microscopy (AM-KPFM) is a powerful technique to measure the contact potential difference (CPD) and work functions of materials at the nanoscale. However, The spatial resolution of AM-KPFM is intrinsically limited by the stray capacitance effect, which is mainly result from the long range of the electrostatic interaction between the cantilever and the sample. As the semiconductor devices getting smaller and more complex, it will become a challenge to obtain their nanometer-scale electrical properties through KPFM. Here, we introduce a special tip exposure technique to develop the coaxial probe with MEMs fabrication. The coaxial structure makes the cantilever and cone insulated, confining the electric field to a small region at the AFM tip Besides, we use finite element method to simulate the spring constant and resonant frequency of the cantilever, making four probes of different geometry to explore the influence of cantilever mechanical properties on the measurement. The fabricated coaxial probes have openings between 0.6 and 1.7 um with a yield more than 80 %. The stray capacitance effect on the coaxial probes were quantitatively analyzed by a method of Electric Tune, which excites resonance of probe through the electrostatic interaction. The results show that for probes of similar spring constant, the one with coaxial structure can reduce the stray capacitance effect effectively, not only decreasing 29 % to 58 % of the electrostatic interaction between cantilever and sample, but enhancing the spatial resolution of AM-KPFM from 1.4 um to 780 nm. For the probe with small spring constant (k<1), we can make its resolution and sensitivity comparable to the commercial probes by making coaxial structure so that it can be beneficial for the electrical analysis of soft materials due to less damage to the sample. From the comparison of four coaxial probes, we also found that the sensitivity and accuracy of AM-KPFM measurement can be promoted by improving the property and quality factor of the cantilever.

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