CoPtCr-SiO2磁性多層膜之垂直式記錄媒體研究｜國立清華大學博碩士論文庫

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研究生：	廖又儀 Yu-Yi Liao
論文名稱：	CoPtCr-SiO2磁性多層膜之垂直式記錄媒體研究 Investigation of CoPtCr-SiO2 Perpendicular Magnetic Recording Media
指導教授：	賴志煌 Chih-Huang Lai
口試委員:
學位類別：	碩士 Master
系所名稱：	工學院 - 材料科學工程學系 Materials Science and Engineering
論文出版年：	2005
畢業學年度：	93
語文別：	英文
論文頁數：	93
中文關鍵詞：	垂直式記錄媒體、殘存應力、訊雜比、讀寫測試
外文關鍵詞：	Perpendicular Recording Media, Residual Stress, Signal-to-noise ratio, Read and Write test
相關次數：	點閱：2 下載：0
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硬碟已經成為人們生活中不可或缺的產品之一，大量且容易獲得的資訊將需儲存在超高記錄的碟片裡，因此人們對於高記錄密度的硬碟的需求將越來越高。之前的硬碟是以水平式記錄碟片為主製成的產品，然而這樣的水平式媒體即將在追求超高記錄密度時遇到物理的極限。是以，目前最重要的是成功發展出垂直式記錄媒體的膜層結構，並進而推進成為新世代的硬碟產品來解決水平式硬碟將會發生的窘境。

本研究將著重在CoPtCr-SiO2 為記錄層的垂直式記錄媒體。首先我們將介紹以Pt和Ru為主的膜層結構，以及單層最佳化的參數進行X-光繞射儀(XRD)、振動樣品測磁力計(VSM)、磁光柯爾效應儀(MOKE)分析晶體結構以及磁性質，並利用穿透式電子顯微鏡(TEM)、X射線能量散佈分析儀(EDS)來進行成分以及微結構分析。接著我們將引入重要的Tb和Ta緩衝層來改善微結構以及磁性質表現，並利用曲率量測的方法輔助分析其改善偏析情況的原因。此外，提升Ru的工作氣壓對於膜層的晶體結構以及磁性的影響，也將利用曲率量測來輔助說明。
最後，我們將把成功發展出的結合記錄層系統以及軟磁層系統的完整膜層結構進行讀寫測試，並觀察其記錄密度以及讀寫性質的表現，其高訊雜比的結果將對於未來推廣至100 Gb/in2超高記錄密度的垂直式記錄硬碟有莫大的益處。

Since Hard Disk Drive have became essential to the public in order to storage their massive information, it is in great demand for ultra-high recording density media. The previous disk is one of the products of longitudinal recording media; however, the physical limit had put a constraint on the development of longitudinal one. As a result, it is urgent to investigate a new type of perpendicular recording media and to push them into real products.
This study has emphasized on the investigation of CoPtCr-SiO2 perpendicular media. To begin with recording layer deposited on Pt/Ru underlayers, it is the fundamental structure for the optimization of CoPtCr-SiO2 perpendicular recording media. We apply Vibrating Sample Magnetometer (VSM), Perpendicular Magneto-Optical Kerr Effect Meter (PMOKE), X-Ray Diffraction (XRD) to analyze magnetic properties and crystallographic characteristics. In addition, we investigate the micro- structure and composition analysis by Transmission Electron Microscope (TEM) and Energy Dispersive X-ray Spectroscopy (EDS). Next, we introduce two series of buffer-layers to improve magnetic properties and microstructure, as well as the enhancement of segregation examined by curvature measurement. In addition, the effect of Ru working pressure on magnetic and structural properties was investigated with curvature measurement.
Finally, we would make the media examined by R&W tests in order to confirm the recording densities and performance for getting into products. As a consequence, the higher SNR performance of our media could promote the recording density to achieve even 100 Gb/in2.

Abstract…………………………………………………………………I
Acknowledgement………………………………………………………III
Contents…………………………………………………………………IV
List of Figures………………………………………………………VII
List of Tables………………………………………………………XVI

Chapter 1 Introduction………………………………………………1
1.1 Motivation…………………………………………………………1
1.2 Outline of the Thesis……………………………………………4

Chapter 2 Background…………………………………………………5
2.1 Principles Perpendicular Recording…………………………5
  2.1.1 Introduction…………………………………………………5
  2.1.2 Basic Concepts of Perpendicular Recording……………5
  2.1.3 Perpendicular Anisotropy and Thermal stability……6
  2.1.4 Magnetic Properties of PMR………………………………8
  2.1.5 Basic Recording Mechanism of PMR…………………9
  2.2.6 Requirements of high density PMR………………………10
2.2 Magnetic Recording Layer (RL)………………………………11
  2.2.1 CoCrPt media………………………………………………13
  2.2.2 Granular CoCrPtO media…………………………………20
  2.2.3 Granular CoPtCr-SiO2 media………………………………23
2.3 Recording Performance of Granular PMR……………………28
  2.3.1 Origin of Media Noise form Layers……………………28
  2.3.2 Influence of Magnetic Cluster Size……………………29
  2.3.3 Inter-granular Interactions……………………………31
       2.3.3.1 Examining form Magnetic Loop…………………32
       2.3.3.2 Remanence Coercivity…………………………33
       2.3.3.3 ΔM measurement and SFD………………………35

Chapter 3 Experimental and Analysis Technique………………38
3.1 Experimental Flowing Chart……………………………………38
3.2 Ultra-High Vacuum Sputtering System (UHV)………………39
  3.2.1 Specification of UHV System……………………………39
3.3 Analysis Technique………………………………………………41
  3.3.1 Vibrating Sample Magnetometer (VSM)…………………41
  3.3.2 Perpendicular Magneto-Optical Kerr Effect Meter… 42
  3.3.3 X-Ray Diffraction (XRD)…………………………………43
  3.3.4 TEM and EDS………………………………………………44
  3.3.5 Atomic Force Microscopy (AFM)…………………………45
  3.3.6 Curvature Measurement……………………………………46
3.4 Read and Write Test……………………………………………47

Chapter 4 Results and Discussions………………………………48
 4.1 Effects of Different Intermediate Layers on PMR………50
    4.1.1 Pt/Ru/CoPtCr-SiO2 Media………………………………51
       4.1.1.1 Effect of recording layer thickness…………51
       4.1.1.2 Effect of working pressure of CoPtCr-SiO2…53
       4.1.1.3 Effect of Ru seedlayer thickness……………53
       4.1.1.4 Effect of Pt underlayer thickness……………55
       4.1.1.5 Ultra-Clean Sputter Process……………………55
    4.1.2 Ta/Pt/Ru/CoPtCr-SiO2 Media……………………………56
       4.1.2.1 Effect of Ta Buffer-layer Thickness…………57
       4.1.2.2 Effect of recording layer thickness…………58
       4.1.2.3 Substrate Effect on PMR…………………………59
    4.1.3 Tb/Pt/Ru/CoPtCr-SiO2 Media……………………………61
    4.1.4 Comparison of these three media……………………61
       4.1.4.1 Stress examination of the media………………63
       4.1.4.2 Microstructure observation……………………65
4.2 Effects of Working Pressure of Ru Seedlayer……………68
    4.2.1 Effect on Pt/Ru/CoPtCr-SiO2 media…………………68
    4.2.2 Stress Effect on Ta/Pt/Ru/CoPtCr-SiO2 media……71
4.3 Full-Stacked Structure…………………………………………76
    4.3.1 Media with Ta/NiFe20/CoFe90/IrMn/CoFe90 SUL……76
    4.3.2 Media with Ta/NiFe20/CoFe90/IrMn/CoFe90¬N SUL…78
    4.3.3 R/W Test…………………………………………………80
         4.3.3.1 PMR without SUL…………………………………80
         4.3.3.2 Full-Stacked PMR………………………………80
         4.3.3.3 SNR result………………………………………83
4.4 100 Gb/in2 PMR…………………………………………………85

Chapter 5 Summary…………………………………………………86

References………………………………………………………………88

                                

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