| Thesis Table of Contents |
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Table of Contents |
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| Acknowledgements..................................................................... | (i) | |
| List of Figures........................................................................... | (vii) | |
| List of Tables............................................................................. | (xiv) | |
| List of Symbols........................................................................... | (xv) | |
| Abstract................................................................................... | (xxi) | |
| List of Publications...................................................................... | (xxix) | |
| Chapter-1: | ||
| INTRODUCTION…………………………..………………....................…. | (1–45) | |
| 1.1 |
Evolution of Thin–Film Transistor (TFT).......................... |
4 |
| 1.2 |
Thin–Film Field–Effect Transistors................................. |
5 |
| 1.2.1 |
Device Physics.......................................................... |
6 |
| 1.2.1.1 |
Conduction Phenomena............................................... |
7 |
| 1.2.1.2 |
Poly–Silicon Film Properties.......................................... |
8 |
| 1.2.1.3 |
Electrical Characteristics of Poly–Si TFT....................... |
10 |
| 1.2.2 |
Advantages............................................................ |
13 |
| 1.2.2.1 |
Single Process Fabrication......................................... |
13 |
| 1.2.2.2 |
Low Temperature Deposition...................................... |
13 |
| 1.2.2.3 |
Isolation................................................................. |
13 |
| 1.2.2.4 |
Assembly................................................................ |
13 |
| 1.2.2.5 |
Substrates............................................................. |
14 |
| 1.3 |
Fabrication of Thin–Film Transistors............................. |
14 |
| 1.3.1 |
Different TFT Structures........................................... |
14 |
| 1.3.2 |
Fabrication Techniques............................................. |
15 |
| 1.3.3 |
Device performance and Feature Size.......................... |
17 |
| 1.3.4 |
Factors Affecting the Electrical Properties.................... |
18 |
| 1.4 |
Comparisons........................................................... |
19 |
| 1.4.1 |
Comparison of Display Technology: CRT vs. AMLCD........ |
19 |
| 1.4.2 |
Comparison of a–Si and poly–Si TFTs........................... |
19 |
| 1.4.3 |
Classification of Thin–Silicon Materials.......................... |
20 |
| 1.5 |
TFT Applications...................................................... |
21 |
| 1.5.1 |
Active–Matrix liquid Crystal Display (AMLCD)................. |
21 |
| 1.5.2 |
Electro–phoretic Display (EDP).................................... |
23 |
| 1.5.3 |
Static–Random Access memory (SRAM)........................ |
26 |
| 1.5.4 |
Image Sensors........................................................ |
27 |
| 1.6 |
Future Trends......................................................... |
29 |
| 1.6.1 |
Poly–Si TFTs on Plastics............................................ |
29 |
| 1.6.2 |
Poly–Si TFTs on Metal Foils........................................ |
30 |
| 1.6.3 |
Poly–Si TFTs on Paper (Organic TFT)........................... |
31 |
| 1.7 |
Device Modeling....................................................... |
32 |
| 1.7.1 |
Analytical Models..................................................... |
34 |
| 1.7.2 |
Table Lookup Model.................................................. |
35 |
| 1.7.3 |
Empirical Model........................................................ |
35 |
| 1.8 |
Scope of Thesis....................................................... |
36 |
| 1.9 | References............................................................. | 40 |
| Chapter-2: | ||
| Quasi Two–Dimensional Modeling of TFT....................................... | (47–83) | |
| 2.1 |
Introduction............................................................ |
49 |
| 2.2 |
Temperature Dependent Model................................... |
50 |
| 2.2.1 |
Threshold Voltage.................................................... |
52 |
| 2.2.2 |
Drain Voltage Characteristics..................................... |
60 |
| 2.2.2.1 |
Field Effect Mobility.................................................. |
61 |
| 2.2.2.2 |
Drain Current Characteristics...................................... |
64 |
| 2.2.2.2.1 |
Linear Region (E<Ec)................................................. |
64 |
| 2.2.2.2.2 |
Saturation Region (E>Ec)........................................... |
65 |
| 2.2.3 |
Transconductance................................................... |
68 |
| 2.2.4 |
Cut–off Frequency and Transit Time............................ |
74 |
| 2.3 |
Summary................................................................ |
80 |
| 2.4 |
References............................................................. |
81 |
| Chapter-3: | ||
| The Kink effect analysis in Post–Saturation Region......................... | (85–106) | |
| 3.1 |
Introduction............................................................ |
87 |
| 3.2 |
Model Formulation.................................................... |
90 |
| 3.2.1 |
Channel Potential..................................................... |
91 |
| 3.2.2 |
Kink Current............................................................ |
96 |
| 3.3 |
Summary.............................................................. |
103 |
| 3.4 |
References............................................................ |
105 |
| Chapter-4: | ||
| Two–Dimensional Potential Distribution Analysis........................... | (107–148) | |
| 4.1 |
Introduction.......................................................... |
109 |
| 4.2 |
Model Formulation.................................................. |
112 |
| 4.2.1 |
Potential Distribution Model...................................... |
112 |
| 4.2.2 |
Horizontal Electric Field at Si– SiO2 Interface................ |
129 |
| 4.2.3 |
Minimum Surface Channel Potential Position................. |
132 |
| 4.2.4 |
Threshold Voltage.................................................. |
135 |
| 4.2.5 |
Sub–threshold Swing............................................... |
139 |
| 4.2.6 |
Transfer Characteristics.......................................... |
142 |
| 4.2.6.1 |
Drain Current......................................................... |
142 |
| 4.2.6.1.1 |
Linear Region......................................................... |
142 |
| 4.2.6.1.2 |
Saturation Region................................................... |
142 |
| 4.2.6.2 |
Transconductance and Cut–off Frequency.................. |
143 |
| 4.3 |
Summary.............................................................. |
145 |
| 4.4 |
References............................................................ |
146 |
| Chapter-5: | ||
| Threshold Voltage Optimization................................................... | (149–181) | |
| 5.1 |
Introduction.......................................................... |
151 |
| 5.2 |
Model Formulation.................................................. |
153 |
| 5.2.1 |
Potential Distribution Model...................................... |
154 |
| 5.2.1.1 |
Effect of Double Gate.............................................. |
161 |
| 5.2.1.2 |
Effect of Gate Dielectric and Work–Function................ |
163 |
| 5.2.2 |
Horizontal Electric Field at Si– SiO2 Interface................ |
164 |
| 5.2.3 |
Threshold Voltage................................................... |
167 |
| 5.2.3.1 |
Impact of Double Gate............................................. |
169 |
| 5.2.3.2 |
Impact of Device Parameters.................................... |
170 |
| 5.2.4 |
Drain Current......................................................... |
172 |
| 5.3 |
Summary............................................................... |
178 |
| 5.4 |
References............................................................ |
180 |
| Chapter-6: | ||
| Improved Gate Transport Device: Multi–Material–Gate Analysis...... | (183–215) | |
| 6.1 |
Introduction.......................................................... |
185 |
| 6.2 |
Model Formulation.................................................. |
189 |
| 6.2.1 |
Potential Distribution Model...................................... |
190 |
| 6.2.1.1 |
Effect of MMG Structures........................................ |
197 |
| 6.2.1.2 |
Effect of Work–Function and Gate–Junction Position Alteration.............................. |
199 |
| 6.2.2 |
Threshold Voltage.................................................. |
202 |
| 6.2.3 |
Drain Current and Channel Length Modulation.............. |
207 |
| 6.2.3.1 |
Linear Region......................................................... |
207 |
| 6.2.3.2 |
Saturation Region................................................... |
208 |
| 6.2.4 |
Transconductance.................................................. |
210 |
| 6.2.5 |
Summary.............................................................. |
211 |
| 6.2.6 |
References............................................................ |
213 |
| Chapter-7: | ||
| Conclusion.................................................................................. | (217–225) | |
| 7.1 |
Summary and Conclusion......................................... |
219 |
| 7.2 |
Future Scope........................................................ |
225 |
| Appendix: Green Function Solution........................................................... | (227–237) | |
