臺灣博碩士論文加值系統

本文中，我們將介紹並探討場效電晶體技術發展中三種重要的議題：蕭特基位能障鍺通道電晶體、鎳金屬鍺化物 及應力效應。
在矽基板上成長一層磊晶應變鍺，並在應變鍺上面成長矽保護層，如此的結構可實現鍺通道的電晶體；而源/汲極則使用鉑金屬來形成P型電晶體的蕭基位能障。我們使用三道光罩的製程來製作元件，並且改善了先前一道光罩製程的缺失。順道提供一些有用的概念以及參數的調整使製程的實行能夠更加完善。
用在以鍺為基底之場效電晶體的電極材質結構中，鎳鍺化合物因其多樣的優點而非常適合用作在以鍺為基底元件電極結構上。我們將說明在不同方向的鍺基底上會隨不同退火之溫度而形成不同鎳鍺化合物並討論之。
我們建構了一種機制來施加外在單軸或雙軸的伸展應力。在應力之下，量測金氧半電容元件(在(100)方向的矽基板上)的平帶電壓的移動，可以觀察到矽的導電帶往下移動以及價電帶往上移動。此外，我們也在(110)方向的矽基板上作了相同的實驗，並且討論其在雙軸的伸展應力下金氧半電容的平帶電壓的移動情況。

In this work, we will introduce and discuss three important topics of advancement of metal-oxide-semiconductor field-effect transistors technology which are Schottky-barrier germanium channel MOSFET, Nickel-germanide, and Strain induced effect.
By using Si-cap/ε-Ge/Si substrate, we can get Germanium channel. And Platinum (Pt) is deposited as metal Schottky-barrier source/drain of p-type MOSFET. The devices are fabricated by three mask process and overcome some shortcomings from one mask process. Some useful concepts and adjustments are also provided to improve the performance of the process.
Formation of electrical contacts in Ge-based MOSFETs have been studied, nickel monogermanide (NiGe) is certainly advantageous for its use as contact material in Ge-based devices. The variation of Ni/Ge structure on different orientation substrate as a function of annealing temperature will be shown and discussed.
We built up a mechanical setup to apply external uniaxial and biaxial tensile strain. By measuring flat-band voltage shift of MOS capacitor on the (110) orientation Si under strain conditions, the reduction of conduction band and the upward shift of valence band edge were observed. Moreover, we done the same experiment on the (110) orientation Si and discuss flat-band voltage shift of MOS capacitor under biaxial strain.

Contents

Chapter 1 Introduction
1.1 Motivation 1
1.1.1 Schottky-barrier Germanium channel pMOSFETs 3
1.1.2 Nickel-Germanide 4
1.1.3 Strain technology 5
1.2 Thesis Organization 5
References 7

Chapter2 Three mask process for Germanium channel
Schottky-barrier pMOSFET
2.1 Introduction 9
2.2 experiment 14
2.2.1 Substrate fabrication 18
2.2.2 Lithography 21
2.2.3 Source/Drain or Gate metal deposition 28
2.2.4 Metal lift-off 29
2.2.5 Oxide deposition and etching 32
2.3 Results and Discussion 34
2.4 Conclusion 42
References 43

Chapter 3 Temperature dependence of Nickel-Germanide formation
3.1 Introduction 45
3.2 Experiment 47
3.3 Results and Discussion 48
3.3.1 Sheet resistance 48
3.3.2 Phase identification 49
3.3.3 Surface roughness 60
3.3.4 I-V characteristic 65
3.4 Conclusion 70
References 71

Chapter 4 Strain-induced effects on MOS capacitor
4.1 Introduction 73
4.2 Strain theory 75
4.2.1 Raman spectroscopy 75
4.2.2 Electron affinity variation and bandgap narrowing with strain 77
4.2.3 Relationship between Ef and Ec (or Ev) under tensile stress 84
4.3 Experiment 87
4.3.1 External mechanical strain setup gear (uniaxial & biaxial ) 87
4.3.2 Substrate preparation and Raman measurement 89
4.3.3 MOS capacitor device fabrication and C-V measurement 92
4.4 Results and Discussion 94
4.4.1 Strain-induced Raman shift 94
4.4.2 Flat-band voltage shifts with strain 96
4.5 (110) substrate biaxial strain 102
4.5.1 Sample cutting 102
4.5.2 Strain-induced Raman shift for (110) sub 103
4.5.3 C-V characteristic variation for (110) substrate 104
4.5.4 Flat-band voltage shifts with strain 106
4.6 Conclusion 107
References 108

Chapter 5 Summary and Future Work
5.1 Summary 110
5.2 Future Work 112

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