臺灣博碩士論文加值系統

本實驗室目前研製之焦平面熱像偵檢器主要分為QWIP及QDIP，由於磊晶結構之故，希望入射光所產生之光電流盡可能被兩端電極收集，以達到理想之偵測度，故在工作區上方增加光柵層，使入射光之電場方向與磊晶法線方向平行，以利電荷被兩端電極收集。但基板未薄化會引起光學串音失真及降溫時FPA與ROIC之間因為熱應力產生之脫層壞點。
因此，本篇論文主要討論應用選擇性蝕刻之選擇比，將GaAs基板移除至1 μm以內的厚度。一來使光柵效果加倍，增加單一像素內的反射次數，進而增強光響應；二來也可減少降溫時FPA與ROIC之間因為應力所產生的脫層壞點。
我們利用檸檬酸當作濕式蝕刻來源，希望在蝕刻上對GaAs與AlxGa1-xAs作特性分析，並研究濕式蝕刻選擇比的最佳條件，增加紅外線偵檢器的偵測度，並降低等效雜訊溫度差(NEDT)，最後再將濕式蝕刻後之影像品質做分析探討。

Developed in our laboratory of thermal imaging focal plane detector consists of QWIP and QDIP, epitaxial structures as there are. The incident light photocurrent is generated by both ends of the electrode to collect as much as possible achievin the desired degree of detection. Therefore, the device top of area is made with the grating layer, so that the electric field incident light is paralleled to the normal direction epitaxy, to facilitate the charge being collected at both ends of electrodes. But the establishment of raster layer will cause distortion of the optical crosstalk and the pixel delimitation of the FPA and ROIC due to thermal stress generated under cycling.
Thus, we discuss the selection ratio impacts of selective etching solvent, for removing the GaAs substrate thickness as much as possible to approach less than 1 μm. To enhence the light response and increase efficiency of reflection within a single pixel using grating scheme. Thus enhancing, it would reduce the hetero-interfacing stress hybridized the FPA and ROIC which results in dead pixels during the cooling cycles.
By means of citric acid used for the etching source, we analysis the physical and optoelectronis characteristics of GaAs and AlxGa1-xAs to achieve the optimized conditions for wet etching proccess,then to improve the performences of infrared focal plane array for detecting and reducing the noise equivalent differential temperature (NEDT). Finally, we analyze the quality of thermal image after the wet etching proccess.

1. 緒論
1.1 研究動機
1.2 研究背景
1.3 論文架構
2. 衡量FPA常用參數及選擇性蝕刻原理
2.1 偵測度
2.2 非均勻度 (Non-Uniformity)
2.3 雜訊等效溫度差( NEDT, Noise Equivalent Difference Temperature)
2.4 選擇性濕式蝕刻機制
2.5 FPA基板蝕刻效能
3. 實驗方法
3.1 元件製備
3.2 選擇性濕式蝕刻實驗架構
3.2.1 注意事項
3.2.2 2-羥基丙烷-1,2,3-三羧酸蝕刻條件
3.3 FPA基板蝕刻實驗架構
4. 結果與討論
4.1 選擇性濕式蝕刻結果
4.2 FPA基板蝕刻結果
4.3 比較與討論
4.3.1 檸檬酸選擇比
4.3.2 FPA蝕刻前後之影像品質、非均勻度及NEDT之比較
5. 結論與建議
參考文獻

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