在本論文中，主要探討以過氧化氫對氮化鎵/氮化鋁鎵/氮化鎵高電子遷移率電晶體之氮化鎵表面進行氧化反應，並生成自然氧化層，藉由此氧化層提升氫離子及氣體感測之能力。
在氫離子感測方面，吾人研製以氮化鎵/氮化鋁鎵/氮化鎵高電子遷移率電晶體為基材，並以過氧化氫進行表面處理之離子感測場效電晶體。本實驗之目的為比較氮化鎵表面與經過氧化氫表面處理之氮化鎵表面自然氧化層(GaxOy)之氫離子感測特性。以GaxOy為感測膜之元件所測得之氫離子感測靈敏度為53.68 mV/pH、電流感測靈敏度為-25.24 μA/pH、遲滯變化為0.4 mV、於pH 7溶液中長時間(12小時)量測之電流偏移量為0.63 μA/hr。與傳統感測氫離子之玻璃電極相比，本實驗研製之元件具有反應時間快、小體積、結構簡單及易與現行之CMOS製程技術相結合等優點。故以氮化鎵自然氧化層作為感測膜之離子場效電晶體非常適合作為生物及化學感測器方面之應用。
在氣體感測方面，吾人研製以氮化鎵/氮化鋁鎵/氮化鎵高電子遷移率電晶體為結構之蕭特基接觸式氣體感測器元件，並各別以鈀金屬與鉑金屬製作蕭特基接觸金屬，用以感測氫氣與氨氣，主要目的在於比較此二元件經過氧化氫表面處理及未經表面處理之氣體感測特性，實驗之元件是在空氣環境中通入不同濃度的氫氣(氨氣)來研究其氫氣(氨氣)響應特性及反應時間等。由於本實驗所研製之元件呈現良好之感測特性，且製程方法能與CMOS製程技術相結合，因此在高效能感測器與微機電系統整合方面極具潛力。

In this study, the native oxide (GaxOy) layer is formed on GaN surface of GaN/AlGaN/GaN high-electron-mobility transistor (HEMT) by immersing into H2O2 solution. The native oxides on GaN surfaces can improve the sensing capability on hydrogen ions and gases.
For hydrogen ion sensing, ion-sensitive field-effect-transistor (ISFET) devices prepared by hydrogen peroxide (H2O2) treatment on GaN/AlGaN/GaN HEMT structure were investigated. The native oxides on GaN surfaces were grown by immersing into H2O2 solution at 300 K. The studied ISFET devices with native oxides were applied to measure the changes of the ion concentrations in an ambient electrolyte. The pH sensitivity of voltage and current was 53.68 mV/pH and -25.24 μA/pH for GaxOy surfaces. In addition, the corresponding long-time drift variation (0.63 μA/hr) and hysteresis property (0.4 mV) of studied ISFET device were investigated. Compared with the conventional pH glass electrodes, the studied ISFETs have many advantages of high sensitivity, short response time, small size, simple structure, easy integration and high compatibility with CMOS technology. Therefore, the studied ISFETs with native oxide sensing films are very promising for biological and chemical sensor applications.
For gas sensing, Schottky-type gas sensors prepared by H2O2 solution on GaN/AlGaN/GaN structure were investigated. Pd and Pt were chosen as Schottky contacts metal to detect hydrogen and ammonia gas, respectively. The main purpose is to compare the gas sensing properties of devices with and without H2O2 treatment. Hydrogen and ammonia sensing behaviors of studied devices are investigated in terms of sensing response and response time with different gas concentrations. Based on excellent results and compatibility of CMOS fabrication techniques of studied devices, the studied devices show the promise for the integration of high-performance sensor and micro-electro-mechanical system (MEMS).

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