臺灣博碩士論文加值系統

本研究分別使用三支靶材In2O3、Ga2O3、金屬Zn或ZnO，以磁控共濺鍍法沈積氧化銦鎵鋅薄膜於玻璃基板表面，並進行退火後將薄膜樣品由橢偏儀、XRD、SEM、EDS、XPS等儀器分別進行薄膜樣品的材料分析，分別觀察薄膜厚度、結晶性、表面形貌以及元素成份鍵結分析;透過UV-Vis光譜儀進行穿透率量測並計算光學能隙，最後由四點探針以及Hall量測薄膜電性來探討材料各種特性之影響。
首先，藉由各別靶材不同沈積功率以了解各別成份對氧化銦鎵鋅薄膜的光學和電性的影響，結果顯示增加In2O3沈積功率對薄膜電阻率明顯下降，其霍爾遷移率和載子濃度會有上升趨勢；增加Ga2O3沈積功率會對薄膜之電阻率、光學能隙有明顯上升，在霍爾遷移率和載子濃度會有下降趨勢，而在短波長區域穿透率上升，光譜吸收邊界顯著地往短波長區域偏移，擬合之薄膜折射率與消光係數會下降；增加Zn靶的沈積功率對薄膜電性影響趨勢與In2O3相同，然而光學穿透率下降與消光係數上升導致光學能隙下降。藉由改變沈積功率對薄膜材料特性之影響，在XRD分析中發現增加Ga2O3沈積功率，其薄膜晶相會從InGaZn7O10 轉變成InGaZn2O5，且晶粒尺寸變小；增加Zn靶材功率，其薄膜晶相會從InGaZn2O5轉變成InGaZn7O10之晶相，且晶粒尺寸變大。
再者，以三支氧化靶進行共濺鍍氧化銦鎵鋅薄膜沈積，研究不同氧氣流量對於薄膜特性影響；結果顯示，當氧氣流量增加時薄膜表面結團晶粒逐漸減少造成光學穿透率隨著上升；而光學能隙下降則是因為氧氣流量增加，薄膜中Ga原子百分比(at.%)減少與Zn at.%上升所致；而在電性方面，隨氧氣流量增加，薄膜內部氧空缺缺陷減少，Ga-Ga鍵結面積減少與Zn-O鍵結面積增加，導致薄膜的電阻率上升和載子遷移率與濃度的下降。最後，藉由增加ZnO靶材之沈積功率，研究ZnO沈積功率對於薄膜特性影響；結果顯示，當ZnO沈積功率增加時，造成薄膜折射率與消光係數均上升，導致平均穿透率與光學能隙都呈下降趨勢。而薄膜結晶程度取決於ZnO成份比例上升，在未摻雜ZnO之氧化銦鎵薄膜，會隨退火溫度的上升應力變化明顯較大，但摻入ZnO成份於氧化銦鎵薄膜中，薄膜應力變化會逐漸變小，當ZnO沈積功率在100W與退火溫度為300℃時薄膜應力變化最小。
關鍵字：共濺鍍氧化銦鎵鋅薄膜、沈積功率、退火溫度、氧氣流量、薄膜特性

Indium-gallium-zinc oxide (In2O3:Ga2O3:ZnO, IGZO) films were deposited on glass substrates at room temperature by using triple targets co-sputtering with two radio-frequency (RF) (In2O3, Ga2O3, ZnO) and one direct-current (DC) (Zn, In2O3) magnetrons. After annealing IGZO films, the film thickness and optical constants of samples were measued by ellipsometer, and opitical transmittance and semiconductor’s electrical properties were measured by UV-Visible spectroscopy and Hall measurement, respectively. Film crystallinity, surface morphology, and compositional analysis were studied by using X-ray diffraction, scan electron microscopy, energy disperssion spectroscopy, X-ray photoelectron spectroscopy, respectively.
First, the individual composition on optical and electrical properties of IGZO films prepared by using various deposition powers for the respective target was investigated. The results show IGZO film resistivity obviously decreased, whereas the Hall mobility and carrier concentration increased with increased In2O3 power. An increased Ga2O3 powers noticeably caused increased film resistivity. However the Hall mobility and carrier concentration decreased. Optical transmittance near short wavelengths from UV-Visible spectroscopy and optical band gap of these films increased considerably with increased Ga2O3 power. In addition, the absorption edge noticeably shifted to a shorter wavelength region, both of fitting refractive index and extinction coefficient decreased with increased Ga2O3 power. The crystallinity of the InGaZn7O10 phase gradually decreased, the phase transformed to the InGaZn2O5 phase with Ga2O3 power, and the grain size becomes smaller. However, Optical transmittance and optical band gap of these films decreased considerably with increased Zn powers, in addition, the extinction coefficient obviously increased near the shorter wavelengths. With an increasing Zn power, the crystallinity of the InGaZn2O5 phase increased and the phase transformed to the InGaZn7O10 phase and the grain size becomes larger.
Furthermore, the effect of O2 gas flow on characteristics of co-sputtered IGZO films prepared by using three targets of In2O3, Ga2O3, ZnO was investigated. The result show the optical transmittance was increased ascribed to surface agglomerate grains of IGZO films decreased with resulting in with increased O2 gas flow, and a decrease of optical band gap resulted from a reduction of Ga atomic ratio (at.%) and an increase Zn at.% when O2 gas flow increased, in terms of the electrical properties with increasing O2 gas flow, increase of resistivity and decrease of carrier mobility and concentration of IGZO films ascribe to reduction of oxygen vacancies, a decrease of Ga-Ga bonding area and an increase of Zn-O bonded area inside the film. Finally, the effect of the ZnO deposition power on characteristics of IGZO films by using various powers of ZnO target was studied. Results show, with an increasing ZnO deposition power, the refractive index and extinction coefficient of the film are increased, resulting in a decreased average transmittance and the optical energy gap. The degree of crystallinity of IGZO films is related to the increase of ZnO composition, the residual stress of the indium gallium oxide (IGO) films with undoped ZnO content significantly changed with an increased annealing temperature. When ZnO composition incorporated into the IGO film, variations of the film stress gradually become smaller. Procecss conditions of the IGZO film with ZnO deposition power at 100W and annealing at 300 ℃ showed the minimum residual stress variation.
Keywords: Co-sputtered Indium-gallium-zinc oxide (IGZO) film, deposition power, annealing temperature, O2 gas flow, film characteristics

摘 要 I
Abstract II
誌謝 IV
目錄 V
表目錄 VII
圖目錄 VIII
第一章 緒論 1
1.1 前言 1
1.2 研究動機 3
1.3 論文架構 4
第二章 共濺鍍IGZO 的文獻回顧 5
2.1 通道材料選擇與非晶氧化物半導體之傳導機制 5
2.2 不同O2流量對In2O3-Ga2O3-ZnO薄膜特性影響 6
2.3 In2O3-Ga2O3-ZnO成份對於IGZO薄膜特性之影響 9
2.4 IGZO薄膜退火製程與材料特性之影響 11
2.5 IGZO薄膜非晶與結晶之特性影響 12
2.6 IGZO薄膜應力之特性影響 14
第三章 薄膜製備和量測方式 16
3.1 靶材的製造過程 16
3.2 基板清潔步驟 16
3.3 共濺鍍薄膜沈積和退火步驟 17
3.3.1 改變三種In2O3、Ga2O3、Zn靶材之沈積功率 17
3.3.2 固定ZnO沈積功率，改變氧氣流量 18
3.3.3 固定氧氣流量，改變ZnO沈積功率 18
3.4 量測裝置 19
第四章 實驗結果與討論 26
4.1共濺鍍In2O3-Ga2O3-Zn之薄膜特性 26
4.1.1改變In2O3沈積功率對共濺鍍IGZO薄膜特性影響 26
4.1.2改變Ga2O3沈積功率對共濺鍍IGZO薄膜之特性影響 32
4.1.3改變Zn沈積功率對共濺鍍IGZO薄膜之特性影響 39
4.1.4小結 46
4.2氧氣流量對共濺鍍In2O3-Ga2O3-ZnO薄膜及不同退火溫度之影響 48
4.2.1氧氣流量對共濺鍍In2O3-Ga2O3-ZnO薄膜之影響 48
4.2.2改變不同退火溫度對共濺鍍IGZO薄膜之影響 62
4.2.3小結 72
4.3改變ZnO沈積功率與不同退火溫度對於IGZO薄膜特性之影響 74
4.3.1改變ZnO沈積功率對於IGZO薄膜特性 74
4.3.2改變不同退火溫度對於IGZO薄膜特性之影響 81
4.3.3小結 89
第五章 結論 91
5.1 結論 91
5.2 未來展望 93
參考文獻 94
作者簡介 98

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