本實驗中將利用具高能隙、高阻值及高吸收係數的非晶矽半導體材料覆蓋在鍺上，並探討其光電特性，首先是利用非晶矽半導體在鍺表面的保護層作用，降低表面缺陷所製作而成的平面式金屬-半導體-金屬結構的光檢測器，藉由此設計來降低暗電流，提高其光暗電流比，並比較其有/無非晶矽氫保護層結構與電漿增強化學氣相沈積氧化層結構的光電特性。其次我們做鍺蕭特基二極體對於表面有無硫化處理之比較其光電特性。
在此我們發現具有非晶矽保護層的鍺光檢測器暗電流為2.48 × 10-7 A與不具非晶矽保護層的鍺光檢測器其暗電流為5.97 × 10-3 A，其具非晶矽氫與不具非晶矽氫的暗電流相差四個數量級，由此可知非晶矽氫是一個很好的保護層，能藉由非晶矽氫覆蓋在鍺表面降低缺陷的特性應用在鍺光檢測器上達到有效降低暗電流的目的。
對於鍺蕭特基二極體而言，硫化過程使其暗電流降低一個數量級，造成光暗電流比增大的趨勢，所以硫化是可行的。
在另一方面我們將沿用上述所發現的特性，對於其覆蓋層非晶矽氫去做變化，共構想出四種結構分別去做其光電特性之探討，入射光源分別為850nm和1310nm，由於鍺吸光波段在於遠紅外光，所以我們利用此兩個光源去分析其四種結構之光電特性。

In this study, reduction of dark current characteristics in the Ge-based Metal-Semiconductor-Metal photodetectors (MSM-PD) with and without hydrogenated amorphous silicon (a-Si:H) and/or with silicon dioxide (SiO2) passivation layer will be discussed. The a-Si:H and SiO2 layer were deposited by using plasma-enhanced chemical vapor deposition (PECVD) system.
At 6V applied voltage, the measured dark current were 1.27×10-8 A, 2.14×10-3 A and 2.5×10-3 A, respectively, for the samples with a-Si:H passivation, without a-Si:H passivation, and with SiO2 passivation layer, respectively. Compared to the sample without a-Si:H layer, the dark current with a-Si:H passivated one was reduced about five orders. Such a result demonstrates that the a-Si:H exhibits passivation function on Ge surface.
Additionally, we used above result to fabrication four structures of a-si:H capping leayer. The 850nm and 1310nm infrared laser light source with fixed power was used to irradiate these samples. It was found that four structures of optoelectronics characteristic by using 850nm and 1310nm infrared laser light source.

封面內頁
簽名頁
授權書．．．．．．．．．．．．．．．．．．．．．．．．．iii
中文摘要．．．．．．．．．．．．．．．．．．．．．．．．iv
英文摘要．．．．．．．．．．．．．．．．．．．．．．．．v
誌謝．．．．．．．．．．．．．．．．．．．．．．．．．．vi
目錄．．．．．．．．．．．．．．．．．．．．．．．．．．vii
圖目錄．．．．．．．．．．．．．．．．．．．．．．．．．x
表目錄．．．．．．．．．．．．．．．．．．．．．．．．．xii

第一章　緒論．． ．．．．．．．．．．．．．．．．．．．．1
第二章　原理．．． ．．．．．．．．．．．．．．．．．．．5
2.1鍺材料基本特性．．．．．．．．．．．．5
2.1-1鍺的基本特性．．．．．．．．．．．．5
2.2金屬-半導體接面理論．．．．．．．．．．．．．5
2.2-1蕭特基接面的接觸機制．．．．．．．．．6
2.2-2蕭特基位障高度的量測．．．．．．．．．7
2.3非晶矽氫的基本特性．．．．．．．．．．．．．8
2.4電漿原理．．．．．．．．．．．．．．．．．．9
2.5光電檢測器原理．．．．．．．．．．．．．．．10
2.5-1光檢測器結構原理．．．．．．．．．．．10
2.5-2金屬-半導體-金屬光檢測器工作原理．．．11
2.6響應率及外部量子效率．．．．．．．．．．．．12
2.6-1響應率及外部量子效率定義．．．．．．．12
第三章　實驗方法與量測．．．．．．．．．．．．．．．．．18
3.1實驗樣品介紹．．．．．．．．．．．．．．．．18
3.1-1材料說明．．．．．．．．．．．．．．18
3.1-2樣品清洗．．．．．．．．．．．．．．．18
3.1-3電漿輔助化學氣相沉積．．．．．．．．．19
3.1-4熱蒸鍍系統．．．．．．．．．．．．．．20
3.2微影(lithography)製程．．．．．．．．．．．．． 21
3.3硫化處理製程．．．．．．．．．．．．．．．．23
3.3-1硫化表面處理步驟．．．．．．．．．．．23
3.4退火系統．．．．．．．．．．．．．．．．．．24
3.4-1快速熱退火系統．．．．．．．．．．．．24
3.5光電量測系統．．．．．．．．．．．．．．．．24
3.5-1 電性量測．．．．．．．．．．．．．．．24
第四章　結果與討論．．．．．．．．．．．．．．．．．．．34
4.1探討硫化與未硫化Au/Ge蕭特基二極體光檢測器． 34
4.1-1有無硫化之比較．．．．．．．．．．． 34
4.1-2硫化過後的響應率及外部量子效率分析．．37
4.2探討不具保護層、具非晶矽氫保護層結構．．40
4.2-1不具保護層，結構(a)．．．．．．．．．．41
4.2-2具非晶矽氫保護層，結構(b)．．．．．．42
4.2-3提高barrier height，結構(c)．．．．．．44
4.2-4具非晶矽氫保護層降低漏電流，結構(d)．．46
第五章　結論．．．．．．．．．．．．．．．．．．．．．．50
參考文獻．．．．．．．．．．．．．．．．．．．．．．．． 51

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