臺灣博碩士論文加值系統

多晶矽薄膜電晶體因為具有較高的載子遷移率，所以被認為可以廣泛的應用
在主動矩陣式液晶顯示器的開關元件上。而為了提升元件的特性，元件的尺寸不
斷的微縮下去，勢必會發生一些非理想效應，此時就有人提出些許方法可以在維
持元件尺寸大小情況下，提升元件的電特性。
多晶矽薄膜電晶體為了提升元件特性，可以對氧化層厚度做適當的微縮，但
是當微縮到一定厚度時，會因為氧化層厚度太薄的關係，而產生不可預期的閘極
漏電流，且氧化層厚度太薄也有可靠度的問題存在;另外，過多的晶粒界面及缺陷
存在於通道中將大幅地劣化多晶矽薄膜電晶體的特性。
金屬誘發側向結晶法減少了晶粒邊界以及存在於通道中的缺陷，而高介電常
數材料當介電層會大幅提升閘極電容值，進而提升元件特性。
本篇論文中，使用了金屬誘發側向結晶法的方式並且搭配高介電常數材料當
介電層，大幅的提升元件的特性，與傳統的固相結晶法搭配二氧化矽當介電層相
比，有著非常好的電特性，包括了載子遷移率和次臨界擺福。另外，其對於短通
道效應量測和變溫量測之電性變化，也將進行探討。

High performance low-temperature poly-Si thin film transistors (LTPS-TFTs) have
been intensively investigated for the application of the active matrix liquid-phase crystal
displays. In this article, high performance LTPS-TFTs are fabricated by using HfO2 gate
dielectric and with Metal-induced lateral crystallization (MILC) channel layer.
MILC LTPS-TFT with High-k Gate Dielectric, high field-effect mobility , ultralow
subthreshold swing are achieved without any defect passivation methods. These
significant improvements are due to the MILC channel film and the very high
gate-capacitance density provided by HfO2 gate dielectric.
In Solid Phase Crystallization (SPC)-TFT’s, the grain boundaries are randomly
oriented. It is also observed in this work that while the MILC-TFT with High-k Gate
Dielectric are less sensitive to short channel effect (SCE).

目錄
論文審定書 ............................................................................................................... i
論文公開授權書 ...................................................................................................... ii
致謝 ......................................................................................................................... iii
摘要 ......................................................................................................................... iv
Abstract ..................................................................................................................... v
表目錄 ................................................................................................................... viii
圖目錄 ..................................................................................................................... ix
第一章 緒論 ...................................................................................................... 1
1-1 薄膜電晶體基本架構 ................................................................................................ 1
1-1-1 薄膜電晶體基本運作原理 .................................................................................... 1
1-2 多晶矽與非晶矽 ........................................................................................................ 2
1-2-1 單晶MOSFET 與多晶矽薄膜電晶體 ................................................................... 2
1-3 再結晶法製程技術 .................................................................................................... 3
1-3-1 準分子雷射結晶法(ELC, Excimer Laser Crystallization) .................................... 4
1-3-2 固相結晶法(SPC, Solid Phase Crystallization) ..................................................... 4
1-4 金屬誘發側向結晶法(MILC, MetalInduced Lateral Crystallization) ..................... 5
1-4-1 金屬誘發側向結晶法(MILC)介紹 ........................................................................ 5
1-4-2 MILC/MIC 之介面影響 ......................................................................................... 7
1-5 短通道效應(SCE, Short-Channel Effect) ............................................................... 8
1-5-1 短通道效應對結晶法之影響 ................................................................................ 9
1-6 高介電常數材料之介電層(High- κ Gate Dielectric) ............................................. 10
第二章 實驗流程與元件製作 ........................................................................ 19
2-1 NTFT 使用固相結晶法 ........................................................................................... 19
2-2 NTFT 使用金屬誘發側向結晶法 ........................................................................... 20
2-2 重要電性參數之萃取 .............................................................................................. 21
2-2-1 臨界電壓 .............................................................................................................. 21
2-2-2 次臨界擺幅 .......................................................................................................... 21
2-2-3 轉移電導(gm) ........................................................................................................ 22
2-2-4 載子遷移率 ......................................................................................................... 22
2-2-5 電流開關比(on/off Ratio) ................................................................................... 23
2-3 實驗動機與目的 ..................................................................................................... 23
第三章 結果與討論 ........................................................................................ 32
3-1 MILC&;High- κ與SPC&;SiO2 之電性比較 ............................................................ 32
3-1-1 MILC&;High-κ 與SPC&;SiO2 之輸出特性曲線(ID-VD) ..................................... 34
3-2 MILC&;High- κ與SPC&;SiO2之通道長度調變 ..................................................... 34
3-3 MILC&;High-κ 之元件比較 .................................................................................... 36
3-4 溫度效應 .................................................................................................................. 37
第四章 結論 .................................................................................................... 39
參考文獻 ................................................................................................................ 59
表目錄
表3-1 NTFT VD=0.1 時之各項電性參數 ..................................................................... 40
表3-2 PTFT VD=0.1 時之各項電性參數 ..................................................................... 40
表3-3 MILC&;High-κ 元件VD=0.1 時之各項電性參數 ............................................. 41
表3-4 SPC&;SiO2元件VD=0.1 時之各項電性參數 .................................................... 41
圖目錄
圖1-1 薄膜電晶體基本架構 ......................................................................................... 12
圖1-2 PTFT 通道累積電洞 .......................................................................................... 12
圖1-3 NTFT 通道累積電子 ......................................................................................... 12
圖1-4 非晶、多晶及單晶等三種晶體的一般形式 ..................................................... 13
圖1-5 固相結晶法(左)與準分子雷射結晶法(右)之表面圖........................................ 13
圖1-6 金屬誘發側向結晶法之長晶示意圖 ................................................................. 13
圖1-7 金屬誘發側向結晶之晶粒示意圖 ................................................................... 14
圖1-8 Ni-Si 反應活化能圖 ......................................................................................... 14
圖1-9 c-Si 在NiSi2/a-Si 介面形成的結晶成長機制 ................................................. 15
圖1-10 Si 與NiSi2晶體結構 ........................................................................................ 15
圖1-11 自我對準下的金屬誘發側向結晶 ................................................................... 15
圖1-12 overlapping MMGBs 以及通道接面能障示意圖 ........................................... 16
圖1-13 漏電流之機制 ................................................................................................. 16
圖1-14 MMGBs offset 之製程示意圖 .......................................................................... 16
圖1-15 MMGB offset 以及通道接面能障示意圖 ....................................................... 17
圖1-16 長通道下能障圖 ............................................................................................... 17
圖1-17 短通道下之能障圖 ........................................................................................... 17
圖1-18 汲極端影響能障示意圖 ................................................................................... 18
圖1-19 固相結晶法與金屬誘發側向結晶法之能障與晶粒邊界分布圖 ................... 18
圖1-20 High-κ Gate Dielectric 多晶矽薄膜電晶體示意圖 ......................................... 18
圖2-1 步驟一 ................................................................................................................. 25
圖2-2 步驟二 ................................................................................................................. 25
圖2-3 步驟三 ................................................................................................................. 25
圖2-4 步驟四 ................................................................................................................. 25
圖2-5 步驟五 ................................................................................................................. 26
圖2-6 步驟六 ................................................................................................................. 26
圖2-7 步驟七 ................................................................................................................. 26
圖2-8 步驟八 ................................................................................................................. 27
圖2-9 步驟九 ................................................................................................................. 27
圖2-10 步驟十 ............................................................................................................... 28
圖2-11 步驟十一 ........................................................................................................... 28
圖2-12 步驟十二 ........................................................................................................... 29
圖2-13 本實驗固相結晶法之結構圖 ........................................................................... 29
圖2-14 步驟四之一 ....................................................................................................... 30
圖2-15 步驟四之二 ....................................................................................................... 30
圖2-16 步驟四之三 ....................................................................................................... 30
圖2-17 步驟四之四 ....................................................................................................... 30
圖2-18 步驟七之一 ....................................................................................................... 31
圖2-19 本實驗金屬誘發側向結晶法之結構圖 ........................................................... 31
圖3-1 .............................................................................................................................. 42
圖3-2 NTFT 在VD=0.1 之轉移特性曲線(ID-VG和gm) .............................................. 42
圖3-3 NTFT 在VD=1 之轉移特性曲線(ID-VG和gm) ................................................. 43
圖3-4 PTFT 在VD=0.1 之轉移特性曲線(ID-VG和gm) ............................................... 43
圖3-5 PTFT 在VD=1之轉移特性曲線(ID-VG和gm) .................................................. 44
圖3-6 MILC&;High-κ 與SPC&;SiO2之NTFT 輸出特性曲線 .................................... 44
圖3-7 MILC&;High- κ 與SPC&;SiO2之PTFT 輸出特性曲線 .................................... 45
圖3-8 MILC&;High- κ NTFF VD=0.1 通道長度調變轉移特性曲線 ........................... 45
圖3-9 MILC&;High- κ NTFF VD=1通道長度調變轉移特性曲線 .............................. 46
圖3-10 SPC&;SiO2 NTFF VD=0.1 通道調變轉移特性曲線 ......................................... 46
圖3-11 SPC&;SiO2 NTFF VD=1通道調變轉移特性曲線 ............................................ 47
圖3-12 NTFT 通道長度調變下的臨界電壓 ................................................................ 47
圖3-13 NTFT 通道長度調變下的次臨界擺幅 ............................................................ 48
圖3-14 MILC&;High- κ PTFF VD=0.1 通道長度調變轉移特性曲線 .......................... 48
圖3-15 MILC&;High- κ PTFF VD=1通道長度調變轉移特性曲線 ............................ 49
圖3-16 SPC&;SiO2 PTFF VD=0.1 通道調變轉移特性曲線 ......................................... 49
圖3-17 SPC&;SiO2 PTFF VD=1通道調變轉移特性曲線 ............................................ 50
圖3-18 PTFT 通道長度調變下的臨界電壓 ................................................................ 50
圖3-19 PTFT 通道長度調變下的次臨界擺幅 ............................................................ 51
圖3-20 MILC&;High-κ 之各元件轉移特性曲線 ......................................................... 51
圖3-21 SPC&;SiO2之各元件轉移特性曲線 ................................................................ 52
圖3-22 MILC&;High-κ NTFF VD=0.1 變溫量測轉移特性曲線 ................................. 52
圖3-23 MILC&;High- κ NTFF VD=1變溫量測轉移特性曲線 .................................... 53
圖3-24 SPC&;SiO2 NTFF VD=0.1 變溫量測轉移特性曲線 ......................................... 53
圖3-25 SPC&;SiO2 NTFF VD=1變溫量測轉移特性曲線 ............................................ 54
圖3-26 NTFT 變溫量測下的次臨界擺幅 .................................................................... 54
圖3-27 NTFT 變溫量測下的漏電流 ............................................................................ 55
圖3-28 MILC&;High- κ PTFF VD=0.1 變溫量測轉移特性曲線 .................................. 55
圖3-29 MILC&;High- κ PTFF VD=1變溫量測轉移特性曲線 ..................................... 56
圖3-30 SPC&;SiO2 PTFF VD=0.1 變溫量測轉移特性曲線 ......................................... 56
圖3-31 SPC&;SiO2 PTFF VD=1變溫量測轉移特性曲線 ............................................ 57
圖3-32 PTFT 變溫量測下的次臨界擺幅 .................................................................... 57
圖3-33 PTFT 變溫量測下的漏電流 ............................................................................ 58

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