臺灣博碩士論文加值系統

此論文探討利用共鍍系統來沉積PZT-Pt鐵電薄膜. 經過熱處理後,我們發 現此PZT-Pt薄膜是以一種"奈米複合材"的微結構存在,在其中Pt原子簇團均勻散佈在PZT的基地上
從成分分析和電性量測我們發現此pZT-Pt奈米複合材在低電壓下操作時擁有較高的殘餘極化量,即使是在一伏特的情況下亦是
因此,一個"低電壓操作"的鐵電記憶體可以利用此方法被生產

In this study﹐the co-sputter method was used to deposit PZT-Pt ferroelectric thin film﹒After post annealing﹐we found that the microstructure of PZT-Pt thin film had a〝nanocomposite〞structure﹐in which﹐Pt clusters were formed and dispersed in the PZT matrix﹒
From composition analysis and electric property measurements﹐it was found that this PZT-Pt nanocomposite films showed an enhanced remanent polarization and a significant polarization signal was still obtained under a low applied voltage of 1 volt﹒It indicates a〝low voltage drive〞FeRAM can be fabricated with such a nanocomposite thin film﹒

Contents
ABSTRACT………………………………………………………………….. I
ACKNOWLEDGEMENT…………………………………………………… II
CONTENTS…………………………………………………………………. IV
LIST OF FIGURE…………………………………………………………. VI
LIST OF TABLE…………………………………………………………… IX
CHAPTER 1 Introduction……………………………………………….. 1
1.1 Prelude……………………………………………………………………... 1
1.2 Motivation…………………………………………………………………. 3
CHAPTER 2 Review……………………………………………………... 5
2.1 Ferroelectric characteristic……………………………………………... 5
2.2 FeRAM……………………………………………………………………... 7
2.3 PZT…………………………………………………………………………. 8
2.3-1 The structure and physical properties of PZT……………………. 8
2.3-2 Effects of PZT domains……………………………………………… 9
2.3-3 Dielectric roperties…………………………………………………... 10
2.4 Important characteristics of PZT film for application in FeRAM…... 11
2.4-1 Leakage current………………………………………………………. 11
2.4-2 Fatigue……………………………………………………………….... 12
2.4-3 Aging…………………………………………………………………… 13
2.5 Electrodes…………………………………………………………………… 14
CHAPTER 3 Experimental Procedure………………………………….... 20
3.1 Target preparation…………………………………………………………. 20
3.2 Substrate preparation……………………………………………………... 20
3.3 Co-sputtering system…………………………………………………….... 21
3.4 Film deposition…………………………………………………………….. 21
3.5 Heat treatment……………………………………………………………… 21
3.6 Structure identification……………………………………………………. 22
3.7 Top electrode fabrication…………………………………………………. 22
3.8 Composition analysis……………………………………………………… 22
3.9 Film thickness measurement……………………………………………… 23
3.10 Chemical state analysis……………………………………………………. 23
3.11 Microstructure examination……………………………………………….. 23
3.12 Depth profile analysis……………………………………………………… 23
3.13 Electrical property measurement……………………………………….... 24
CHPTER 4 Results and Discussions……………………………………... 31
4.1 The composition of PZT-Pt films………………………………………… 31
4.2 X-Ray diffraction pattern…………………………………………………. 31
4.3 SIMS depth profile…………………………………………………………. 32
4.4 TEM & microstructure……………………………………………………. 32
4.5 AFM images………………………………………………………………... 34
4.6 ESCA information…………………………………………………………. 35
4.7 Electric properties…………………………………………………………. 36
4.7-1 P-E hysteresis loops………………………………………………….. 36
4.7-2 dielectric constant……………………………………………………. 37
4.7-3 The influence of Pt content in Pr and Ec………………………….. 39
4.7-4 The parameter of〝Pr / Ec * K〞………………………………….. 39
4.7-5 Leakage current………………………………………………………. 40
4.7-6 Fatigue performance………………………………………………… 41
4.8 Thickness dependence…………………………………………………….. 41
4.9 Effect of different annealing process……………………………………. 42
CHAPTER 5 Conclusion…………………………………………………. 85
CHAPTER 6 Reference…………………………………………………… 86

CHAPTER 6
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