使用電漿輔助氣相沉積系統(PECVD)製作非晶矽p-i-n型光二極體已經使用非常廣泛，目前市面上已經有許多利用此項技術所作之產品上市，然而在生醫檢測用之目的方面的要求，卻比一般之應用要求更為嚴刻，是故為了製造出更佳效能的光二極體，我們所訂定的條件也必須更加嚴謹•在製作出p-i-n型光二極體前，我們必須先分析本質非晶矽半導體的材料特性是否已達到我們製作p-i-n型光二極體的要求•利用光學特性FTIR了解材料結構上之特性可以幫助我們了解所長薄膜的條件，繼而幫助我們調整參數已達要求•除此之外藉由照光與不照光下的導電系數亦可幫助我們了結薄膜特性，經由長膜參數的調整我們已經可以在單一腔體內製作出照光與不照光下的本質非晶矽導電率比值可達五個數量級，此代表本質層之污染已經降至可接受之範圍，如此我們便可以將這本質層應用在p-i-n型光二極體•除此之外，因為所使用之電漿輔助氣相沉積系統為單一腔體製程，是故不同層與層之間的相互污染將有可能影響最後製造之p-i-n光二極體之電性，是故再度完p-型層後，作一簡單之氫氣沖刷處理流程，亦可減低互相污染，在我們的實驗裡，我們已經將p-i-n光二極體之電性照光比暗電流達到七至八個數量級•有如此高之數量及方可作為生醫檢測知使用，除此之外，p-i-n光二極體之電性照光對550nm波長之光照效率亦達70%•此一波長的光乃是X-光經由光轉化層CsI(Tl)所轉化出之波長峰值所在，代表轉換之效率亦非常高•

Using Plasma-Enhanced Chemical Vapor Deposition (PECVD) system to deposit a-Si:H p-i-n photo diode or photovoltaic solar cell is very common. In order to manufacture higher performance photo diode, we first analyze the optical and electrical properties of the most important light-absorption layer – intrinsic hydrogenated amorphous silicon film. The photo conductivity to dark conductivity ratio of i-layer ( ) is about 105. And because the a-Si:H p-i-n photo diode is deposited directly in a single PECVD chamber, so the contamination to i-layer by dopant atoms will be a critical issue. But we had raise up the photo-to-dark current ratio of a-Si:H p-i-n photo diode to 107 ~ 108 by the specific chamber purge process. And the external quantum efficiency η can reach more than 70% for 550nm light. Because of the high performance of the a-Si:H p-i-n photo diode, this makes it possible for the use in the medical application.

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