利用四氟化碳及氮之雙重電漿處理於氧化鉿鋁金屬-絕緣體-半導體電容之研究

Abstract

在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 在過去的四十年內，非晶矽二氧化薄膜已經被廣泛應用於金屬 -絕 緣體 -半導體相關結構之中 半導體相關結構之中 半導體相關結構之中 半導體相關結構之中 。隨著元件的微縮，閘極氧化層厚度也不斷縮小，導致閘極直接穿隧漏電流增加。因高介電常數材料能有效降低漏電流與提升元件效能，所以近年來已被廣泛研究。在眾多材料之中，氧化鉿鋁是非常有淺力的一種高介電常數材料，特別是應用於六十五奈米後互補式金屬氧化物半導體場效電晶體製程，因為它有相對較高的結晶溫度與介電常數。在本篇論文中，以Al/Ti/HfAlO/Si金屬-絕緣體-半導體電容器做為控制樣品。結合沉積前四氟化碳電漿處理及沉積後電漿氮化處理，我們稱為雙重電漿處理。我們將討論不同電漿條件對於電性及可靠度之影響，包含電容大小、漏電流、遲滯效應、CVS、及崩潰電壓等特性。我們發現經雙重電漿處理後的樣品，有較高的電容值、較低的漏電流密度與較小的遲滯電壓。這是因為氟原子可以抑制絕緣層和矽基板之間的氧化層成長，而氮原子可以修補介電質中的缺陷。我們也討論漏電流傳輸機制，可分為蕭基發射(Schottky emission)，佛倫克爾-普爾發射（Frenkel-Pool emission）以及佛勒-諾德海姆穿隧(Fowler-Nordheim tunneling)。

Amorphous silicon dioxide films have been applied popularly for gate dielectric in MOS-based structure in the past forty years. However, the continuing scaling down of device has significantly reduced the thickness of gate dielectric film, leading to gate direct tunneling leakage current increase. Therefore, high-k gate dielectric material has been extensively studied in recent year, which could effectively reduce leakage current and improve device performance. Among many dielectric material, hafnium aluminate (HfAlO) is considered one of the promising high-k gate material for 65 nm technology node and beyond CMOSFETs, owing to the relatively crystallization temperature and its moderate dielectric constant. In this thesis, Al/Ti/HfAlO/Si metal-insulator-semiconductor capacitors were used as control samples. The process which combined CF4 pre-deposition plasma and post-deposition plasma nitridation, we called it dual plasma treatment. We discussed the electrical characteristics and reliability properties of the film under different plasma conditions, including capacitance, leakage current, hysteresis, constant voltage stress and breakdown behavior. After dual plasma treatment, the capacitors exhibit higher capacitance, lower leakage current density, and lower hysteresis voltage. It might be that fluorine could suppress the interfacial layer growth between the HfAlO/Si interface, the nitrogen also can repair defects at bulk dielectric to decrease the leakage current. We also discussed the current conduction mechanisms, which could be attributed to Schottky emission (SE), the Frenkel-Poole (FP) emission and Fowler-Nordheim (FN) tunneling in different ranges of electric field.