以MSM結構設計之感測元件應用於表面電漿共振量測之研究

Abstract

SPR 是一種廣泛應用於各種方面，如物理、化學與生物感測上的技術。傳統的SPR感測需要使用光感測器，如CCD相機或光二極體等來進行感測。這些裝置通常體積較大，並且難以與其他裝置如半導體裝置等進行整合。 近期的研究將光感測器，如蕭基二極體與SPR感測器結合，以電信號方式感測SPR。蕭基二極體由金屬與半導體構成，當入射光線的能量大於蕭基能量障壁，金屬中的電子便能跨越蕭基能量障壁，進入半導體，成為電流。這個過程稱為內部電子放射。當SPR發生時，會加強內部電子放射，因而讓蕭基二極體的電流上升。藉由這個過程，SPR的光學信號被轉換為電信號。 在這篇論文中，我們設計了一個由金和氧化鋅構成的MSM蕭基感測器。我們使用有限時域分析模擬不同氧化鋅厚度造成的SPR表現變化，並且實際量測裝置的SPR曲線證明之。我們架構了一個以鎖相迴路放大器為核心的量測系統，整合SPR感測系統以及電感測系統，作為實驗的量測。 SPR量測以及電信號量測在系統中同時被量測，量測的結果顯示雖然電訊號的最小偵測極限大於SPR的光學量測，但我們設計的裝置依然可以擁有將SPR光學訊號轉為蕭基二極體電訊號的能力。

Surface Plasmon Resonance (SPR) has been widely applied on physical, chemical and biological sensing. Traditional SPR sensing method use photodetector such as CCD camera and photodiode. Such device is huge and hard to integrate with other device such as semiconductor device. Novel method integrate SPR sensor with photodetector such as Schottky detector. It transform SPR optical signal to electrical signal. Schottky detector is constituted by metal and semiconductor. When the energy of incident light exceeds the Schottky barrier of Schottky detector, the electron of metal will cross the Schottky barrier and become current, which is called internal photoemission. When SPR occurs, the internal photoemission of Schottky detector will be enhanced, and the current increases. The optical signal of SPR therefore transform to electrical signal. In this thesis, we design a MSM Schottky detector consist of Au and ZnO. We use FDTD method to simulate the effect of ZnO thickness on SPR performance, and measure SPR Curve of device to prove the simulation. We construct a measurement system integrate SPR measurement system and electrical measurement system. The core of measurement system is lock-in amplifier. The current of Schottky detector is measured simultaneously with SPR optical signal. The measurement result shows although the lowest detection limit is not as good as SPR measurement , such device is still capable of detect SPR optical signal via Schottky detector electrical signal.