由於矽製程在元件持續微縮下，將會遇到許多無法克服的非理想效應，然而二維過渡金屬硫化物電晶體並無短通道效應，因此單層二維過渡金屬硫化物被視為有希望可用於未來元件微縮的材料，而對於晶圓規模的製造，單晶且密集的單層奈米帶二硫化鉬有望被用於先進的邏輯與記憶體元件製程。在此論文中，我們展示了在(100)的β-氧化鎵之壁架結構(-201)晶面上成長出高密度、公分等級且自對準的單晶單層奈米帶二硫化鉬，不論是從實驗結果或是計算來看，奈米帶二硫化鉬會沿著β-氧化鎵之壁架結構面成核與生長，除此之外，我們也藉由掃描穿透式電子顯微鏡去證實奈米帶二硫化鉬的單晶結構與方向。奈米帶二硫化鉬可以被轉印到任何的基板上，而作為成長基版的β-氧化鎵亦可在機械剝離後重新使用。最後，我們將奈米帶二硫化鉬作為通道材料配合單晶單層六方氮化硼作為氧化層去製作場效電晶體，在室溫下，電晶體具有電流開關比108，電子遷移率約63cm2/Vs的表現

As the silicon process continues to shrink devices scale, it will encounter a lot of non-ideal effects, but two-dimensional(2D) transition metal dichalcogenides(TMDs) transistor has no short channel effect. Therefore, two-dimensional transition metal dichalcogenides monolayers have been considered promising for future device scaling. For wafer scale manufacturing, dense arrays of single-crystal, globally aligned TMD monolayer nanoribbons are desired in advanced logic and memory devices. Here, we demonstrate a ledge-directed epitaxy (LDE) of dense arrays of centimeter-long, self-aligned, monolayer and predominantly single-crystalline MoS2 nanoribbons on β-gallium(III) oxide (β-Ga2O3) (100) substrates. Experimental observation and density function theory (DFT) simulation suggest that nucleation and growth of the nanoribbons follow the β-Ga2O3 ledges. The stitching of unidirectional seeds into continuous, single-crystal and -orientation MoS2 nanoribbons was confirmed by dark field-scanning transmission electron microscopy (DF-STEM). The MoS2 nanoribbons can be readily transferred to arbitrary substrates while the underlying β-Ga2O3 can be re-used after mechanical exfoliation. Our prototype MoS2 nanoribbon and single crystal monolayer hBN as oxide layer based field effect transistor exhibits an on-off ratio of 108 and room temperature carrier mobility of 63 cm2/Vs

目次
致謝 i
摘要 ii
Abstract iii
目錄 iv
圖目錄 vii
表目錄 x
第一章 緒論 1
1.1 研究背景 1
1.2 研究動機 3
1.3 論文大綱 4
第二章 文獻回顧 5
2.1 二維材料 (Two-Dimensional materials) 5
2.1.1 過渡金屬硫化物(TMDs) 6
2.1.2 二硫化鉬(MoS2) 8
2.1.3 二硫化鉬電晶體 9
2.1.4 六方氮化硼(hBN) 12
2.1 物性分析 14
2.2.1 拉曼光譜(Raman Spectroscopy) 14
2.2.2 光激螢光光譜(Photoluminescence) 15
2.2.3 掃描電子顯微鏡 (Scanning Electron Microscope, SEM) 16
2.2.4 二次諧波產生分析(Second Harmonic Generation) 16
2.2-5 導電原子力顯微鏡(Conductive Atomic Force Microscope) 17
第三章 材料分析與元件製備 18
3.1 材料成長 18
3.2 材料分析 20
3.2.1拉曼分析(Raman Analysis) 20
3.2.2 光激螢光分析(Photoluminescence Analysis) 21
3.2.3 掃描電子顯微鏡(Scanning Electron Microscope) 22 3.2.4 二次諧波產生分析(Second Harmonic Generation) 22
3.2.5導電電子顯微鏡分析(Conductive Atomic Force Microscope) 23
3.3 元件製備流程 25
3.3.1 閘極氧化層二氧化鉿(HfO2)沉積 26
3.3.2 二維材料轉印方法 26
3.3.3 源極/汲極黃光對位與金屬沉積方法 27
第四章 元件電性量測與結果 29
4.1 Flake MoS2、nanoribbon MoS2與film MoS2電晶體I-V特性 29
4.2 hBN inserted MoS2 電晶體I-V特性 34
第五章 總結與未來展望 39
參考文獻 40

圖目次
圖1.1-1 Moore's Law 2
圖1.1-2 25K時電子遷移率與TSOI之關係 2
圖1.1-3 FinFET微縮示意圖 3
圖1.1-4 通道材料之墊子遷移率與基板厚度 4
圖2.1-1 二維材料種類與類別 5
圖2.1-2 二維材料能隙圖 6
圖2.1-3 過渡金屬硫化物組成元素 7
圖2.1-4 過渡金屬硫化物層數不同之能帶圖 7
圖2.1-5 二硫化鉬結構示意圖 8
圖2.1-6 二硫化鉬拉曼光譜 9
圖2.1-7 a.單層二硫化鉬在SiO2/Si 光學影像圖 b.在單層二硫化 鉬上電極光學影像圖 c.電晶體結構示意圖 10
圖2.1-8 電晶體轉移曲線圖(Id-Vg) 10
圖2.1-9 a.化學氣相沉積系統圖 b.二硫化鉬成長在基板上光學影像圖 c-d. 二硫化鉬原子力顯微鏡圖與其厚度量測 11
圖2.1-10 650度化學氣象沉積之單層二硫化鉬電晶體轉移曲線圖(Id-Vg) 12
圖2.1-11 六方氮化硼結構示意圖 13
圖2.1-12 單層六方氮化硼之拉曼光譜 13
圖2.2-1 拉曼光譜示意圖 14
圖2.2-2 光激螢光光譜示意圖 15
圖2.2.3 二次諧波產生示意圖 16
圖3.1-1 (100)β-Ga2O3之晶體結構 19
圖3.1-2 奈米帶二硫化鉬成長過程示意圖 19
圖3.1-3 AFM下奈米帶二硫化鉬成長過程圖 19
圖3.1-4 奈米帶二硫化鉬SEM圖 19
圖3.2-1 MoS2/β-Ga2O3 拉曼光譜 20
圖3.2-2 二硫化鉬與PL圖 21
圖3.2-3 奈米帶二硫化鉬SEM圖 22
圖3.2-4 奈米帶二硫化鉬SHG圖與AFM圖 23
圖3.2-5 導電電子顯微鏡配置與I-V圖 24
圖3.2-6 奈米帶二硫化鉬形貌圖與其電流映射圖 24
圖3.3-1 元件製備流程 25
圖4.1-1 電晶體結構示意圖 30
圖4.1-2 Flake MoS2 電晶體ID-VG圖 31
圖4.1-3 Flake MoS2 電晶體ID-VD圖 31
圖4.1-4 Nanoribbon MoS2 電晶體ID-VG圖 32
圖4.1-5 Nanoribbon MoS2 電晶體ID-VD圖 32
圖4.1-6 Film MoS2 電晶體ID-VG圖 33
圖4.1-7 不同晶體結構二硫化鉬元件之電子遷移率箱形圖 33
圖4.2-1 hBN inserted MoS2電晶體結構示意圖 35
圖4.2-2 多晶hBN inserted flake MoS2電晶體ID-V 35
圖4.2-3 單晶hBN inserted nanoribbon MoS2電晶體ID-VG圖 36
圖4.2-4 單晶hBN inserted nanoribbon MoS2電晶體ID-VD圖 36
圖4.2-5 有無多晶hBN電晶體之電子遷移率箱形圖 37
圖4.2-6 有無單晶hBN電晶體之電子遷移率箱形圖 37
圖4.2-7 電晶體之電子遷移率箱形圖 38

表目次
表4.2-1 各元件之電性參數 38

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