Physics-based compact modeling and parameter extraction for InP heterojunction bipolar transistors with special emphasis on material-specific physical effects and geometry scaling (eBook)

Dissertation

Tobias Nardmann (Autor)

eBook Download: PDF

2017 | 1. Auflage
244 Seiten
Books on Demand (Verlag)
978-3-7448-4706-3 (ISBN)

Infos

The trend in modern electronics towards ever higher frequencies of operation and complexity as well as power efficiency requires a whole palette of different technologies to be available to circuit designers for various applications. While MOSFETs dominate the digital world, they have apparently reached their top analogue performance around the 65nm node. Emerging technologies such as CNTFETs offer excellent properties such as very high linearity and speed in theory, but have yet to deliver on those promises in practice. Heterojunction bipolar transistors (HBTs), on the other hand, offer a number of key advantages over competing technologies: A very high transconductance and therefore a relatively low impact of a load impedance on the transistor operation, a high transit frequency and maximum frequency of oscillation at a comparatively relaxed feature size and favorable noise characteristics. Like all semiconductor devices, HBTs can be fabricated in diferent semiconductor materials. The most common are SiGe HBTs, which even today reach values above (ft; fmax) = (300; 500) GHz and are projected to eventually reach the THz range. However, HBTs fabricated in III-V materials offer a versatile alternative. Depending on the materials that are used, III-V HBTs can be the fastest available bipolar transistors (competing only with HEMTs, also fabricated in III-V materials, for the title of fastest available transistors overall), offer very high breakdown voltages and therefore excellent power-handling capability, show good linearity or low noise figures at high frequencies. Typical applications for III-V HBTs include handset PAs, high-effciency and high-speed amplifiers as well as high-speed oscillators . Overall, III-V-based HBTs and especially InP HBTs are excellent candidates for future high-speed communication circuits. The goal of this work is to include important effects occurring in III-V materials in a compact model for circuit design in a physical, yet intuitive way in order to aid deployment of III-V HBTs in prototypes and products. Additionally, the parameter extraction procedure for the compact model is described and analyzed in detail so an accurate, physics-based parameter set can be obtained. Finally, the agreement of the model with measurements is demonstrated for three different III-V HBT processes.

Tobias Nardmann received his Dr.-Ing. degree in electrical engineering from Technische Universität Dresden, Germany, in 2017, where he is currently a postdoctoral researcher. His research interests include the compact modeling of III-V HBTs, compact model parameter extraction, small-signal measurement and calibration and TCAD simulations.

Inhalt

Title Page 2
Copyright 3
Dedication 4
Danksagung 6
Abstract 8
Table of Contents 12
List of Symbols 16
1 Introduction 20
2 Modeling III-V based HBTs 24
2.1 Introduction 24
2.2 Differences between SiGe and III-V HBTs 25
2.2.1 III-V material properties 25
2.2.2 Vertical composition 27
2.2.3 Top view and cross section 31
2.3 Compact modeling 34
2.3.1 Principles of compact modeling 34
2.3.2 The HICUM compact model 36
2.3.3 Existing III-V compact models 38
2.4 Numerical simulations of III-V materials 40
2.4.1 Material properties 41
2.4.2 n+ ? n ? n+ structure 42
2.4.3 HBT structure 45
2.4.4 Conclusions 48
3 Model extensions 50
3.1 Introduction 50
3.2 Temperature dependence of the base current components 50
3.3 Collector-emitter parasitic capacitance 52
3.4 Multi-region junction capacitance 54
3.4.1 Standard compact model capacitance description 55
3.4.2 Derivation for the multi-region model 57
3.4.3 Voltage limiting 61
3.4.4 Model verification 64
3.4.5 Temperature dependence 66
3.5 Collector transit time 67
3.5.1 Low-current transit time 67
3.5.2 Medium current transit time 81
4 Compact model parameter determination 94
4.1 Introduction 94
4.2 Parameter determination 95
4.2.1 Parameter determination methodology 95
4.2.2 On-wafer measurements 97
4.2.3 Pulsed measurements 100
4.3 Evaluation of extraction methods for series resistances 105
4.3.1 Evaluating extraction methods 105
4.3.2 Investigated process technologies 108
4.3.3 Methods for the emitter resistance 109
4.3.4 Methods for the collector resistance 125
4.3.5 Methods for the base resistance 134
4.4 Single device parameter extraction 146
4.4.1 Junction capacitances 146
4.4.2 Diode parameters 148
4.4.3 Series resistances 149
4.4.4 Avalanche current parameters 150
4.4.5 Temperature coefficients and thermal resistance 151
4.4.6 Transit time parameters 155
4.4.7 Transfer current parameters 160
4.4.8 Additional extraction steps 162
4.4.9 Summary 163
4.5 Geometry-scalable parameter extraction 164
4.5.1 Technology description 166
4.5.2 Test structures 167
4.5.3 Geometry separation 172
4.5.4 Scaling of other parameters 176
4.5.5 Discussion 177
5 Model application 182
5.1 250 GHz InP technology 182
5.2 500 GHz InP technology 187
5.3 GaAs technology 193
6 Summary and outlook 196
Bibliography 200
Appendix A: Material parameters for numerical device simulations 216
A.1 Band gap 216
A.2 Band gap narrowing 217
A.3 Effective mass 219
A.4 Dielectric constant 219
A.5 Impact ionization 219
A.6 Recombination 220
A.7 Low-field mobility 222
A.8 Field-dependent mobility 223
A.9 Energy relaxation time 223
Appendix B: Impact of relative permittivity on the collector junction capacitance 226
Appendix C: Supplementary figures for model verification 228
C.1 250 GHz InP process 229
C.2 500 GHz InP process 235
C.3 GaAs process 239

Produkt-Details

• Erscheint lt. Verlag: 28.8.2017
• Sprache: englisch
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• ISBN-10: 3-7448-4706-3 / 3744847063
• ISBN-13: 978-3-7448-4706-3 / 9783744847063