USB 介面之 N-型矽晶圓/金蕭特基能障之表面電漿子共振生物感測器設計、製作與量測驗證

Abstract

本研究設計、製作並驗證了一種N型摻雜矽（N doped Si）和金（Au）的表面電漿子共振（SPR）裝置，目的是探索它在生物感測方面的應用潛力。在設計階段，本研究利用COMSOL和MATLAB進行模擬。COMSOL模擬顯示，隨著入射光波長增加，電場強度也跟著增加，這跟本研究對矽晶圓的預期一致。模擬結果也指出，表面不同寬度的光柵微結構對電場分布與強度有明顯影響。MATLAB模擬中，觀察不同厚度的金層和入射光角度對反射光強度的影響，發現約48到51奈米的金層厚度能產生最強的SPR效果。這給本研究實驗提供了重要參考。本研究改變SPR裝置的設計並分別嘗試使用金屬探針、導線和USB進行電學性質測量，相比前人僅能使用探針進行量測，使用USB量測並不會大幅降低電流訊號，相比導線和金屬探針更方便、安全且快速地獲得訊號。在裝置製作過程中，本研究用鋁基板作為基底材料，在N型摻雜矽上蒸鍍48奈米的金層，這結構不僅有效產生SPR效應，還能形成蕭特基能障，進一步優化了晶片性能。實驗結果顯示，本研究設計的裝置在電流-電壓特性曲線上呈現蕭特基電阻特性，照射600奈米紅光後能產生約0.5 nA的光電流。為改進裝置，本研究也嘗試使用FRP板作為基板，蒸鍍金和鋁後再黏貼於基板上，測量電流-電壓曲線時，也能顯示蕭特基電阻性質。此外在其中一個樣本上，發現在未焊接電子零件時，測量電流-電壓曲線，能表現蕭特基電阻的性質，然而焊接電子零件後，電流-電壓曲線變得接近線性，推測晶片可能在高溫焊接時受損，導致蕭特基接觸的性質消失。最後本研究測量不同濃度的葡萄糖水溶液，從增加的光電流訊號來看，隨著溶液折射率增加，增加的電流訊號呈線性減少。本研究設計的N doped Si/Au SPR感測器展示了良好的蕭特基電阻性質，未來將進一步優化設計，提升性能並探索更多應用場景。

This study designed, fabricated, and validated an N-doped silicon (N-doped Si) and gold (Au) surface plasmon resonance (SPR) device to explore its potential in biosensing applications. During the design phase, simulations were conducted using COMSOL and MATLAB. The COMSOL simulation showed that the electric field intensity increased with the incident light wavelength, which aligned with expectations for the silicon wafer. The results also indicated that different widths of grating nanostructures significantly affected the light field distribution and electric field intensity. In the MATLAB simulation, the effects of gold layer thickness and incident light angle on reflected light intensity were analyzed. It was found that a gold layer thickness of about 48 to 51 nm produced the strongest SPR effect, providing crucial guidance for the experiments. This study modified the SPR device design and tested electrical measurements using metal probes, wires, and USB connections. Compared to previous studies that only used probes, the USB method allowed for safer, faster, and more convenient signal acquisition without significantly reducing current signals. During the fabrication process, an aluminum substrate was used as the base material, with a 48 nm gold layer deposited on the N-doped silicon. This structure not only effectively generated the SPR effect but also formed a Schottky barrier, further improving chip performance. Experimental results showed that the device exhibited Schottky resistance characteristics on the current-voltage (I-V) curve and generated about 0.5 nA of photocurrent under 600 nm red light. To improve the device, this study experimented with FRP boards as substrates, depositing gold and aluminum before attaching them to the substrate. We can also observe the Schottky resistance characteristics from the I-V curve measurements. For one sample, Schottky resistance characteristics were observed before electronic components were soldered, but the curve became more linear after soldering. It is suspected that the chip was damaged by high temperatures during soldering, causing the Schottky contact properties to disappear. Finally, the device was tested with glucose solutions of different concentrations. The results showed that the increased current signals decreased linearly as the refractive index of the liquid increased. The N-doped Si/Au SPR sensor designed in this study demonstrated good Schottky resistance properties. Future work will focus on optimizing the design, improving performance, and exploring more application scenarios.