金屬-絕緣體-半導體與金屬-絕緣體-金屬結構之高介電薄膜原子層化學氣相沉積

Atomic Layer Deposition of High-k Thin Films in Metal-Insulator-Semiconductor and Metal-Insulator-Metal Structures

張哲豪(Che-Hao Chang)

指導教授 ： 吳泰伯

國立清華大學/工學院/材料科學工程學系/博士(2007年)

摘要

此篇論文重點在於以原子層化學氣相沉積技術成長氧化鋁和氧化鉿薄膜於矽、砷化銦鎵、鉑、氧化鉑、氮化鈦基板上。首先，在第二章中，我們基於原子層化學氣相沉積技術的優勢原理，提供實際方法控制氧化鋁和氧化鉿薄膜製程用於氫原子保護之矽基板上。在邏輯和記憶體運用上，經過成長動力學、均勻性、成分、鍍率、和階梯覆蓋性的製程最佳化，氧化鋁和氧化鉿薄膜可得到較佳之電性。依據最佳化之塊材性質結果，超薄氧化鋁和氧化鉿電容的界面性質，例如界面層電性等效厚度和界面層捕獲密度，在適當的後沉積處理溫度中進一步被改善。氧化鋁和氧化鉿複合結構也被進一步研究用來減少介電層固定電荷。
其次，在第三章中，當使用四(氮-乙基-氮-甲基胺基)鉿和水作為前趨物，原子層化學氣相沉積之氧化鉿成長於砷化銦鎵上時被發現有界面自我清潔現象。藉由四(氮-乙基-氮-甲基胺基)鉿和砷化銦鎵表面之配位基取代反應，砷化銦鎵之原生氧化層可被移除。由高頻電容電壓關係可得到清楚之累積到空乏轉變，而暫態電容電壓關係可得到反轉態。由此可知此結果緩和了氧化鉿和砷化銦鎵異質結構之費米能階釘牢問題。非常低之漏電流也被發現在此金屬氧化物半導體結構中。
最後，在第四章中，7.3 nm的氧化鋁和氧化鉿薄膜成功地被成長於水氣電漿處理之鉑電極上。從x-ray光電子光譜結果，顯示鉑表面藉由水氣電漿處理被改質成氫氧化鉑。表面氫氧化的鉑增進了前趨物的化學吸附反應性並因此而改善了氧化物的初始成長、減少界面的碳殘留量、以及減少電容結構之漏電流。

關鍵字

原子層化學氣相沉積 ； 高介電薄膜 ； 金屬-絕緣體-半導體 ； 金屬-絕緣體-金屬

並列摘要

In this thesis, the high-κ oxides of Al2O3 and HfO2 are investigated on Si, InGaAs, Pt, PtOx, and TiN substrates by atomic layer deposition. First, in Chapter 2, we apply the methodology based on the fundamental benefits of ALD to control the Al2O3- and HfO2-ALD process on the H-terminated Si substrate. Growth kinetics, uniformity, composition, deposition rate, and step coverage were optimized to get the best electrical properties of ALD-Al2O3 and -HfO2 films for logic and memory applications. According to the optimization of bulk properties, the ultrathin Al2O3 and HfO2 capacitors were investigated to improve the interfacial properties, e.g., the EOT of IL and Dit, by moderate PDA temperature. Finally, Al2O3 and HfO2 composite structure were investigated.
Second, in Chapter 3, an interfacial self-cleaning phenomenon is found in the atomic layer deposition of HfO2 on In0.15Ga0.85As/ GaAs substrate, using Hf(NCH3C2H5)4, i.e. TEMAH, and H2O as the precursors. The native oxides of InGaAs were all satisfactorily removed from the interface through ligand exchange (substitution) reactions with the TEMAH precursor. This relieves the Fermi-level pinning in the HfO2/ InGaAs heterostructure, as verified by the clear transition from accumulation to depletion in high-frequency capacitance-voltage relations and inversion in quasistatic measurement. A very low leakage current was also found from the metal-oxide-semiconductor (MOS) capacitors of Au/ Ti/ HfO2/ InGaAs.
Finally, in Chapter 4, ultrathin Al2O3 and HfO2 conformal films of ~7.3 nm thick were successfully grown by atomic layer deposition (ALD) on Pt electrodes in-situ treated with hydrous plasma. The x-ray photoelectron spectroscopy reveals that the Pt surface can be effectively modified to Pt(OH)2 by the hydrous-plasma treatment. This improves the growth of the oxide films and reduces the leakage in the Al2O3 and HfO2 capacitors. The enhancement of chemisorption reactivity of the hydroxylated surface of Pt is responsible for the improvements in the growth and electrical properties of the ALD films.

並列關鍵字

ALCVD ； high-k thin film ； MIS ； MIM