研究生: |
吳政彥 Cheng-Yen Wu |
---|---|
論文名稱: |
表面處理效應於氧化鋯薄膜電容器之電性分析 The Effect of Surface Treatment on the Electrical Properties of ZrO2 MIS Capacitors |
指導教授: |
龔正
Jeng Gong |
口試委員: | |
學位類別: |
碩士 Master |
系所名稱: |
電機資訊學院 - 產業研發碩士積體電路設計專班 Industrial Technology R&D Master Program on IC Design |
論文出版年: | 2006 |
畢業學年度: | 95 |
語文別: | 中文 |
論文頁數: | 93 |
中文關鍵詞: | 高介電材料 、依時性介電崩潰 、表面處理 、氧化鋯 |
外文關鍵詞: | high-k, time-dependent-dielectric breakdown(TDDB), ZrO2, surface treatment |
相關次數: | 點閱:99 下載:0 |
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本實驗中,我們使用射頻磁控濺鍍法沈積(氧化鋯)ZrO2薄膜,並於沈積前後分別利用H2O2及dilute HCl進行表面處理,之後將其製成ZrO2電容器,並利用物性及電性上的分析去觀察其特性上的變化,最後再利用依時性介電崩潰去分析其可靠度,並探討韋伯斜率且與文獻上的結果作比較。
在物性分析上,利用XRD確認(氧化鋯)ZrO2薄膜尚未結晶,並利用FTIR、XPS結果,推論使用H2O2 pre-treat會於矽基版表面形成一層矽氧化物,而從SIMS分析的結果,間接證明了之前的推論,並觀察到此矽氧化物可以減低(鋯原子)Zr擴散進入矽基板的深度,最後再由TEM直接證明之前的推論,並發現有使用H2O2 pre-treat的試片,其介面層厚度為5.9 nm較未使用H2O2 pre-treat的試片7.7 nm 來的小。
在電性分析上,利用高低頻法C-V量測得知兩種表面處理對於固定電荷及介面狀態密度,都有一定程度上的改善。而使用dilute HCl post-treat的試片其漏電機制為Poole-Frenkel emission所主導,不同於使用H2O2 pre-treat的試片由schottky emission所主導,推論是由於Zr-Cl的鍵結能僅339 kJ/mol較Si-O的鍵結能452 kJ/mol小的多,所以在較高溫低場下Zr-Cl鍵結容易被打斷,使得薄膜內部缺陷增加而出現Poole-Frenkel emission機制。
於可靠度分析上,利用依時性介電崩潰分析有無使用H2O2 pre-treat的試片,發現有使用H2O2 pre-treat的試片其韋伯斜率為1.2而未使用H2O2 pre-treat的試片僅為0.9,且比較同在-1 V之生命期,發現有使用H2O2 pre-treat的試片其生命期為2 × 106 sec 較未使用H2O2 pre-treat的試片其生命期為2 × 104 sec大了兩個數量級。
The effect of surface treatment on the electrical properties of ZrO2 MIS capacitor was studied with pre-H2O2 and post-diluted HCl. The interface state was reduced from 5.6 × 1013 cm-2 to 4 × 1012 cm-2. From TEM analysis, the interfacial layer reduced from 7.7 nm to 5.9 nm after H2O2 pretreatment. The dielectric constant of ZrO2 film from C-V measurement increased from 5.54 to 7.3 due to reduced interfacial layer. The Cl incorporated into ZrO2 film during post-treatment resulted in further increase of the dielectric constant. The conduction mechanism was studied. Poole-Frenkel emission was found above 450 K and at low field (< 0.6 MV/cm) for samples with only post-treatment, this is most likely caused by Zr-Cl bond breaking under high temperature.
In the reliability issues, the Weibull slope was obtained from time dependent dielectric breakdown (TDDB) measurements. The extracted Weibull slope (β) of 1.2 and 0.9 were obtained from the samples with H2O2 pretreatment and with no treatment, respectively. The lifetime of the sample with H2O2 pretreatment is 2 × 106 seconds while lifetime of samples with no treatment is 2 × 104 seconds.
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