臺灣博碩士論文加值系統

本文探討鈦金屬薄膜在受應變矽/矽鍺磊晶基材上的界面反應。
本實驗利用電子槍蒸鍍系統，於室溫將30 nm.厚度之鎳金屬薄膜沈積到矽鍺基材上，分別在600-850 ℃氮氣保護下，使用快速熱退火處理三十秒以進行固態反應。接著使用四點探針量測法、X光繞射儀、穿透式電子顯微鏡、X光能量散射光譜儀以及歐傑電子光譜儀等分析方法來鑑定固態反應後之薄膜的電性、相結構以及界面反應。
利用X光繞射儀鑑定出Ti/strained Si系統中之穩定相的組成。發現在700 ℃退火30秒後已經有C54-TiSi2生成。與Ti/blank Si 系統比較發現溫度提前。利用穿透式電子顯微鏡觀察試片，發現在Ti/strained Si 系統中非晶層的活化能量較Ti/blank Si 系統的小。這是由於在基材中受到拉伸應力的影響，使得矽原子較容易擴散而使得活化能下降及C54-TiSi2 提早生成。

Interfacial reactions of Ti on strained Si epitaxially grown on Si0.7Ge0.3 have been investigated.
35-nm-thick strained Si films were epitaxially grown on 300-nm-thick Si0.7Ge0.3 at 500℃ by solid source molecular beam epitaxy(MBE). The stress measurements of top strained Si layer were carried out by Raman spectra and high resolution X-ray diffraction (rocking curves). 30-nm-thick Ti thin films were evaporated by an electron beam evaporation system on the strained Si substrates at room temperature. The solid-phase reactions were induced in a rapid thermal annealing (RTA) system by annealing at temperatures ranging from 600 to 850 ℃ for 30 seconds. The resulting films were characterized by transmission electron microscopy (TEM), Rutherford backscattering spectrometry, glancing-angle x-ray diffraction method, energy dispersive x-ray spectrometry, and four-point probe method.
The stresses of top strained Si layer determined by high resolution x-ray diffraction (rocking curves) and Raman spectra were about 2.5 to 3.0 GPa and tensile. From cross-sectional high-resolution TEM micrograph of as-deposited Ti/strained Si samples, it was found that the amorphous interlayer of as-deposited Ti/strained Si sample ( tstrained Si≒3.0 nm ) is thicker than that of as-deposited Ti/bare Si sample ( tbare Si≒2.0 nm ). A sharp drop in sheet resistance was found for Ti on the tensily stressed samples at 700 °C. On the other hand, for Ti on stress-free samples a sharp drop in the sheet resistance was found as the annealing temperature was increased to 750 ℃. It indicated that appreciable high-resistivity C49—TiSi2 to low-resistivity C54—TiSi2 transformation occurred. The phases of annealed samples were characterized by glancing-angle x-ray diffraction method. The C54 TiSi2 phase was found to be present in 700 ℃ annealed Ti/strained Si samples. The activation energy of Ti/Si/Si0.7Ge0.3 system (∼0.8 ± 0.2 eV) is lower than that of Ti/Si system (∼1.0 ± 0.2 eV). The results clearly showed that in Ti/Si/Si0.7Ge0.3 system the tensile stress reduces the activation energy for the growth of Ti/Si amorphous interlayer.

Abstract 4
Chapter 1 Introduction 6
1-1 An Overview………………………………………………………6
1-2 The Formation and Applications
ofSilicide………………………7
1-2-1 Self-aligned Silicide Process (Salicide).......7
1-2-2 Polycide Process……………………………………….8
1-3 Ti/Si System……………………………9
1-4 Si1-xGex/Si Heterostructures ……………….9
1-5 Properties of strained Si………………….15
Chapter 2 Experimental Procedures18
2-1 Substrates……………………………………………………..18
2-2 Wafer Cleaning……………………………………………….…18
2-3 Thin Film Deposition ……………………..19
2-4 Stress Measurement………………………………………………20
2-4-1 The Mechanism of Raman Scattering…………………..20
2-4-2 Epitaxial Stress Measurement by Raman spectra technology………………………………………….….21
2-4-3 The Mechanism of High Resolution X-Ray
Diffraction………………………………………….….22
2-4-4 Epitaxial Stress Measurement by High Resolution
X-Ray Diffraction Technique…………………………...23
2-5 Heat Treatments for Solid-Phase Reactions………………….24
2-6 Analyses……………………………………....24
2-6-1 Sheet Resistanc Measurement…………………….24
2-6-2 X-Ray Diffractometor (XRD)………………….….25
2-6-3 Transmission Electron Microscop Observation….26
2-6-4 Sample Preparation for TEM Observation...….....26
2-6-5 Rutherford Backscattering Spectrometry (RBS) Analysis..28
Chapter 3 Results and Discussion 30 3-1 Composition Analysis………………………………....30
3-2 Stress Measurements………………….30
3-2-1 Raman spectra……………...30
3-2-2 High Resolution x-ray Diffraction…....32
3-3SheetResistanceMeasurements………………………………....33
3-4XRD Analysis……………………………………34
3-5TEMAnalysis…………………………………………………..35
Chapter 4 Summary and Conclusions 39
References 42
Figure Captions 47
Tables 52
Figures 55

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