在此篇論文中，主要研究以氮化鎵/氮化鋁鎵/氮化鎵結構研製蕭特基式氣體感測器，與其他材料(例如砷化鎵、矽)相比，氮化鎵的寬能隙能帶、高電子飽和速度、高載子濃度和高崩潰電壓，用來製作元件有高速、低雜訊且可在高溫下操作的特性，而與氮化鋁鎵接面處所存在的高密度二維電子氣(2-DEG)能使氮化鎵/氮化鋁鎵/氮化鎵基底的感測器展現良好的感測能力。以過氧化氫表面氧化處理和射頻濺鍍的方式在蕭特基感測區分別生成高質量的氧化層(GaOx、Ta2O5和Ga2O3)，這些氧化層有寬能隙能帶和高介電係數的特性，能夠大幅降低元件表面的漏電流，因而提升感測特性。
利用快速對流沉積法(RCD)在原有的催化金屬鉑上塗上單層二氧化矽奈米球，於此之上再蒸鍍上一層鉑薄膜，運用兩層修飾的方式大幅度增加表面粗糙度和體表面積比，增加元件的吸附能力。另外，而在催化金屬上方利用快速蒸鍍法製造奈米粒子能增加表面積及增強溢出效應的功能。最後章節運用無電鍍的方式取代傳統熱蒸鍍在蕭特基區域形成感測層，相比於熱蒸鍍，無電鍍的製程過程有著簡易操作、低溫、低耗能且製程時間短的優點，不僅能避免熱損壞，較粗糙的表面也能使元件提升吸附能力。高質量氧化層、無電鍍、奈米粒子跟二氧化矽奈米球等修飾方法使表面漏電流降低、吸附能力增加、粗糙度提升皆有利於元件的感測倍率、速度等效果。

In this thesis, the main research is to develop Schottky type gas sensors with GaN/AlGaN/GaN-based structure. Compared with other materials (such as GaAs and Si), GaN material has the characteristics of wide energy bandgap, high electron saturation speed, high carrier concentration, and high breakdown voltage, which can be employed in high-speed and low-noise devices and operate at high temperature. In addition, the presence of the heterojunction between GaN and AlGaN, the high-density two-dimension electron gas (2-DEG), can results in GaN/AlGaN/GaN-based sensors exhibit good sensing performances. High-quality oxide layers (GaOx, Ta2O5, and Ga2O3) were formed on the Schottky sensing area by hydrogen peroxide treatment and radio frequency sputtering, respectively. These oxide layers have the characteristics of wide energy bandgap and high dielectric coefficient, which can significantly reduce the surface leakage current and improve sensing performance.
By using rapid convection deposition (RCD) method, a uniform SiO2 nanospheres (NS) monolayer was coated on the catalytic platinum metal, and then a platinum film was deposited on it by vacuum thermal evaporation (VTE). This two-layer modification method greatly increases the surface roughness and the surface area/volume ratio resulting in enhancing the adsorption ability of the device. In addition, the use of nanoparticles by rapid evaporation method on the catalytic metal can increase the surface area and enhance the “spill-over” effect. In the last chapter, electroless plating (EP) method was used to replace traditional thermal evaporation to form the sensing region. Compared with thermal evaporation, the process of electroless plating method has the advantages of simple operation, low temperature, low energy and short process time. The EP method not only can avoid heating damage but also cause the rougher surface, which leads to larger surface area and thus improves the adsorption ability. The use of high-quality oxide layers, electroless plating, nanoparticles and SiO2 nanospheres can cause surface leakage current reduction, adsorption ability improvement, and roughness increase resulting in promoting sensing response and sensing speed.

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