研究生: |
蔡輔桓 Tsai, Fu-Huan |
---|---|
論文名稱: |
應用電荷汲引技術於先進金氧半電晶體高介電閘層之缺陷探測分析研究 Study of Profiling Traps in High-k Gate Dielectric for Advanced MOSFETs by Applying Charge Pumping Technique |
指導教授: |
張廖貴術
Chang-Liao, Kuei-Shu |
口試委員: |
楊文祿
趙天生 |
學位類別: |
碩士 Master |
系所名稱: |
原子科學院 - 工程與系統科學系 Department of Engineering and System Science |
論文出版年: | 2011 |
畢業學年度: | 99 |
語文別: | 中文 |
論文頁數: | 93 |
中文關鍵詞: | 電荷汲引技術 、可靠度 、電晶體 、高介電系數介電層 、溫度電應力 |
相關次數: | 點閱:3 下載:0 |
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以高介電係數材料取代二氧化矽成為金氧半元件閘極介電層來改善元件微小化伴隨的漏電流問題,然而在材料替換的過程中,產生許多額外的問題。如電荷捕獲,臨界電壓飄移,載子遷移率下降等,因此應用在高介電係數閘極介電層電晶體上的界面陷阱及氧化層陷阱可靠度分析因應而生。
論文首先介紹電荷汲引技術(charge pumping)的基本原理與量測方法,藉由載子的捕捉與複合得到之淨電流,稱為汲引電流(Icp)。將不同的汲引電流換算後可得到對應的界面陷阱密度與能量分佈狀況,以及得到邊緣陷阱密度與空間分佈的關係。
其次說明,傳統電荷汲引方式中存在量測延遲上的問題,界面陷阱容易因為快速的回復行為而使量測到的結果產生誤差。遂利用不間斷的連續脈波同時施加應力與量測,達到不間斷量測的方式,成功觀察到界面缺陷的快速回復過程並藉以獲得較正確的界面缺陷密度。
接著分析經過Fluorine電漿介面處理元件的BTI可靠度表現,使用氟電漿處理與700oC沉積後退火溫度者有最佳的可靠度表現。然後藉由電荷分離與電荷汲引技術,分離PBTI與NBTI後不同缺陷對臨界電壓飄移的貢獻,儘管在NBTI中有較大量的界面缺陷增生,卻只在PBTI中觀察到明顯的臨界電壓飄移,表示主要影響臨界電壓飄移的為氧化層缺陷的電荷捕捉而非界面缺陷密度。
最後討論進行BTI可靠度量測時,所需注意的量測溫度選擇問題,當給定量的缺陷數目下,在不同量測溫度下量測會因臨界電壓的變動而造成高估或低估電應力結果。並且改變溫度亦會產生額外的溫度效應,造成臨界電壓回復現象。因此進行BTI的電應力實驗時,在量測溫度的選擇上,除了保持相同的起點與終點溫度。還必須在與應力溫度相同的溫度下進行,避免量測溫度效應。對擷取缺陷活化能與評估可靠度上有著不可或缺的影響。
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