近場掃描微波顯微鏡的研發製作

Development of Near-field Scanning Microwave Microscope (NSMM)

賴奎元(Lai Kwei-Yuan)

指導教授 ： 盧志權

國立臺灣師範大學/理學院/物理學系/碩士(2015年)

https://doi.org/10.6345/NTNU202204759

摘要

鐵磁共振儀是研究自旋動力學不可或缺的強大工具。多年前本實驗室以向量網路分析儀(VNA)為基礎開發了鐵磁共振儀(FMR)。現在我們致力於將研究延伸到局域性的鐵磁共振量測(LFMR)，而近場描微波顯微鏡(NSMM)正是達成此目標的必要條件。

文主要呈現自行研發製作掃描穿隧顯微鏡(STM)和近場掃描微波顯微鏡(NSMM)的過程，包含兩套顯微鏡架設所需的核心理論、儀器介紹、開發過程。最後，以特製的樣品來檢驗STM與NSMM的解析度與靈敏度。

關鍵字

近場 ； 微波 ； 顯微鏡 ； 表面阻抗 ； 掃描穿隧電子顯微鏡 ； 局域鐵磁共振

並列摘要

In order to achieve surface impedance topography and submicron level magnetic domain image as well as extend our greatest interest and expertise of spin dynamic measurement, so called ferromagnetic resonance (FMR), to local ferromagnetic resonance measurement(LFMR), we are dedicated to developing a near-field scanning microwave microscope (NSMM).

Self-configured scanning tunneling microscope (STM) and NSMM employing RHK R9 SPM controller, n.point C.300 piezoelectric stage and Agilent N5230C network analyzer are demonstrated in this dissertation. Developmental processes can be mainly divided into STM part and NSMM part. In STM part, designs of main body, vibration isolation, automatic approach system, and tip fabrication are demonstrated. In NSMM part, two different configurations adopting microwave components, vector network analyzer (VNA), and NI my DAQ, are discussed. Finishing constructing, various samples were employed to test performance of the instruments. Cu-coated 4.7 GB DVD fabricated by pulse laser deposition (PLD) was used as STM test sample. For NSMM’s test samples, Au/Si alternatively stripped samples with three different dimensions, 25 um/ 25 um, 10 um/ 10 um, and 2 um/ 18 um, were fabricated by electron beam lithography (EBL) and vacuum thermal evaporation deposition (VTED). An AFM standard silicon test sample with dimensions of 5 um in x, y and 180 nm in z was also scanned to discriminate the influence of 100-nm thickness of Au strips from surface impedance.

Hundred-nanometer spatial resolution has been achieved by our STM with set-point current 0.8 nA and bias voltage 1.5 V. A set of chemically-etching equipment are also developed and are capable of producing sharp tips with apex diameter less than 100 nm under parameters of 4 V KOH, 8 V etching voltage, and 2 V cut-off voltage. This apex is very ideal for scanning probe microscope (SPM) uses. Most critically, the self-developed NSMM configuration using VNA, PC and NI my DAQ. This novel yet simple configuration enables our NSMM to miraculously accomplishλ/10000-wavelength-relative resolution as well as sensitivity less than 0.01 dB while working over 13 GHz.

並列關鍵字

near-field ； microwave ； microscope ； surface impedance ； scanning tunneling microscope (STM) ； local ferromagnetic resonance (LFMR)

參考文獻

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