利用快速熱退火與雷射引致退火製作矽化鎳及其在光偵測器上的應用

Study of the Nickel Silicide Formation by Utilizing Rapid Thermal Annealing and Laser Induced Annealing Processes and its Application to the Photo Detector

李承諭(Cheng-Yu Lee)

指導教授 ： 陳學禮

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.03233

摘要

矽化鎳由於可以降低內部連接導線的電阻率，故被廣泛地運用在積體電路製程中。然而在本篇論文中，我們將會提出一個新穎的矽化鎳應用在光偵測器上。我將會將此研究分為三個部分闡述我們的概念。首先我將會利用不同的製程技術在矽基板上形成矽化鎳，接下來藉由薄膜理論的分析求得矽化鎳在可見光、深紫外光及真空紫外光的光學常數並對其設計抗反射結構。最後，我將提出矽化鎳在光偵測器上的可行性並爲了更進一步的研究而設計出所謂的光閘極金氧半電晶體。

我們分別利用快速熱退火與雷射引致退火形成矽化鎳並討論非晶矽在退火製程中所扮演的角色。除此之外，並提出了一個不同於現今半導體製程中自我對準矽化物的圖樣化技術，即結合雷射引致退火與相位光罩的應用直接曝出設計好的矽化鎳圖樣。藉由此技術，可以使用相同的微影曝光之深紫外光雷射在晶圓上區域性及快速的得到想要的矽化鎳圖樣。

由於矽化鎳的折射率與消光係數皆相當高，如果單純使用和積體電路製程相容的光學薄膜堆疊，將無法得到一個效果好的抗反射結構。所以我會同時結合光學薄膜堆疊與金字塔結構抗反射層而將反射率由53%最多降低到0.07%。將此抗反射結構應用在光偵測器上，可以進一步的增加此光偵測器的靈敏度。

當我們在矽基板上形成矽化鎳時，將會有蕭特基接面存在其間。我們利用簡單的二極體光偵測器去驗證此蕭特基接面的確可以在照光時產生電子電洞對。並結合我們先前設計的金字塔抗反射結構，發現此結構的確可以增加光電流。利用此概念我們期望可以設計出一個完全只需要利用照光，而不需要在閘極外加偏壓就能驅動元件運作的金氧半電晶體光偵測器。

關鍵字

矽化鎳 ； 光偵測器 ； 抗反射層 ； 快速熱退火 ； 準分子雷射 ； 相位光罩

並列摘要

Nickel silicide has been widely used as gate materials of transistor in integrated circuit processes for the reduction of interconnection resistance. In this thesis, we will provide a novel application of nickel silicide on photo detector. We will divide this research into three parts to expound our concept. Firstly, we utilize different annealing processes to form nickel silicide. Secondly, we apply thin film theory to obtain optical constant of nickel silicide in visible, deep ultraviolet light and vacuum ultraviolet regimes and design antireflection structures for nickel silicide. Then, we show the feasible application of nickel silicide on photo detector and design the so-called photo gate MOS transistor to do further study in the future work.

We utilized rapid thermal annealing (RTA) and laser induced annealing (LIA) processes to form nickel silicide and discussed the role of amorphous silicon in annealing process. By utilizing the laser induced annealing process with phase mask, we demonstrate a novel silicide patterning technique, which is different from salicide process used in present semiconductor fabricated process. With this technique one can use a deep ultraviolet lithography exposure tool to form and pattern silicide locally and rapidly.

Because both refractive index and extinction coefficient of nickel silicide film are large, using optical thin film stacks, which compatible with semiconductor fabricated processes can not obtain acceptable antireflection effect. We utilized optical thin film stacks combining with pyramid structures could further reduce reflection from 53% to 0.07%.

When nickel silicide is formed on silicon substrate, there is a Schottky barrier between silicon and nickel silicide. We utilized a simple diode to prove this Schottky barrier can be served as electron-hole pair generated center and further combining pyramid antireflection structure on it to verify this structure can gain more photocurrent. By this concept, we design a photo MOS transistor which can be turn on only by illumination instead applying voltage on gate.

並列關鍵字

NiSi ； silicide ； photo detector ； RTA ； Excimer laser ； phase mask

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