表面電漿共振是一種用於檢測在結構上或者是材料成份上有微小變化的技術，但這樣的技術需要先激發出表面電漿子才能達到如此的成效。為了激發出表面電漿子，已經有很多方法被提出來，而其中又可大略分類為菱鏡耦合和波導耦合兩種主要的方式。雖然菱鏡耦合的結構較為簡單，但由於龐大的菱鏡侷限了整合到一塊微小的生物感測器。基於這樣的原因提供了選擇波導耦合的動機。

為了達到元件微小化的目的因而整合在精巧的生物感測器，絕緣層覆矽的技術提供了很好的選擇。由於和標準的補償式金氧半製程技術相容，在製程上允許達到次微米的矽波導結構。而且又由於矽和二氧化矽之間的折射率有很大的差值，更能進一步將波導結構形成矽線波導，因此適合於觀測奈米尺寸下表面電漿共振和感測物的作用。

在這篇論文中，藉由在矽線波導和鋁之間放置一層薄薄的二氧化矽形成混合式電漿波導，利用金屬對外部感測物的反應因而在金屬的邊界產生表面電漿極化子，進一步和波導自身的模態進行干涉從而達成生物感測的目的。為了能作為靈敏的生物感測器，對於元件的相關特性如二氧化矽的厚度或者鋁本身的厚度及波導的寬度進行探討和優化。根據模擬的結果，靈敏度可以高達3700dB/RIU因而達成生物感測的目的。

Surface plasmon resonance (SPR) is a highly sensitive technique to detect small perturbation in structures or composition by utilizing interaction between the thin metal layer and analyte under condition for excitation on surface plasmon. To achieve condition for excitation on surface plasmon, several methods have been proposed and among those prism-coupling and waveguide-coupling are two main approaches. Although the structure of prism-coupling is simpler than waveguide-coupling, the bulk of prism limits its potential for integrating on a compact biosensor and promotes the motivation to choose waveguide-coupling.
To make photonic device integrated on a chip, silicon-on-insulator technology provides a good choice due to its fully compatible process with standard process of complementary metal-oxide-semiconductor (CMOS), which allows a silicon waveguide to be fabricated on a submicron scale to fulfill photonic integrated circuit on a miniature. Besides, the large refractive index difference between silicon dioxide and silicon layers further reduce the device size to form silicon wire waveguide, a good platform accompanying with metal to observe interaction between surface plasmon resonance with analyte.
In this thesis, the simulation of hybrid plasmonic waveguides was demonstrated to interfere the waveguide mode in silicon wire waveguide with surface plasmon polariton generated at interface of aluminum (Al). In order to be a sensitive probe for biosensing, an optimization on device structure is necessary on the aluminum thickness, silicon dioxide layer, and silicon wire waveguide width. Simulation results demonstrated sensitivity can be up to 3700 dB/RIU to analyte, giving a good example to apply on biosensing.

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