Radamson / Thylen Monolithic Nanoscale Photonics-Electronics Integration in Silicon and Other Group IV Elements

1. Auflage 2014
ISBN: 978-0-12-419996-5
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 182 Seiten

Silicon technology is evolving rapidly, particularly in board-to-board or chip-to chip applications. Increasingly, the electronic parts of silicon technology will carry out the data processing, while the photonic parts take care of the data communication. For the first time, this book describes the merging of photonics and electronics in silicon and other group IV elements. It presents the challenges, the limitations, and the upcoming possibilities of these developments. The book describes the evolution of CMOS integrated electronics, status and development, and the fundamentals of silicon photonics, including the reasons for its rapid expansion, its possibilities and limitations. It discusses the applications of these technologies for such applications as memory, digital logic operations, light sources, including drive electronics, optical modulators, detectors, and post detector circuitry. It will appeal to engineers in the fields of both electronics and photonics who need to learn more about the basics of the other field and the prospects for the integration of the two. - Combines the topics of photonics and electronics in silicon and other group IV elements - Describes the evolution of CMOS integrated electronics, status and development, and the fundamentals of silicon photonics

Henry H. Radamson received an M.Sc. degree in physics and the Ph.D. degree in semiconductor materials from Link”ping University in Sweden, in 1989 and 1996, respectively. In 1997, he joined the Royal Institute of Technology in Stockholm as a senior scientist, where he has been an Associate Professor since 2001.

Autoren/Hrsg.

Radamson, Henry

Thylen, Lars

Inhaltsverzeichnis

1;Front Cover;1
2;Monolithic Nanoscale Photonics—Electronics Integration in Silicon and Other Group IV Elements;4
3;Copyright Page;5
4;Contents;6
5;Acknowledgments;10
6;Introduction: Scope and Purpose of Book;12
7;1 Metal Oxide Semiconductor Field Effect Transistors;16
7.1;Part One: Basics of Metal Oxide Semiconductor Field Effect Transistors;17
7.1.1;Surface Space–Charge Regions in MOSFETs;19
7.1.2;Leakage Components in MOSFETs;22
7.1.3;Subthreshold Current;22
7.1.4;Gate–Oxide Leakage;23
7.1.5;S/D Junction Leakage;23
7.1.6;MOS Capacitors;23
7.1.7;Static Characterization of MOSFETs;24
7.1.8;Transfer from 2D to 3D Nanoscaled Transistors;28
7.1.9;Gate Integration in FinFETs;30
7.1.10;Parasitic Sources in MOSFET Structure;31
7.1.11;Lithography of Nanoscaled MOSFETs;32
7.1.12;Sidewall Transfer Lithography;32
7.2;Part Two: Strain Engineering in Group IV Materials;33
7.2.1;Strain Design for MOSFETs;37
7.2.2;Strain Effect on Carrier Mobility;38
7.2.3;Basic Definitions;38
7.2.4;Carrier Mobility in MOSFETs with Strained Si Channel;39
7.2.5;Strain and Critical Thickness;43
7.2.5.1;Global Critical Thickness of SiGe Layers;43
7.2.6;Critical Thickness of SiGe Layers on Patterned Substrates;45
7.2.7;Critical Thickness of SiGe Layers Grown on Nano Features;45
7.2.8;Strain Measurements and Applications;46
7.2.8.1;Strain Measurement;46
7.2.8.2;Raman Spectroscopy;46
7.2.8.3;TEM Analysis;48
7.2.8.4;High-Resolution X-Ray Analysis;48
7.3;Part Three: Chemical Vapor Deposition of Group IV Materials;50
7.3.1;Selective and Nonselective Epitaxy;51
7.4;Part Four: Improvement of the Channel Mobility;57
7.4.1;Effect of Recess Shape in S/D;57
7.4.2;Channel Materials and Mobility;59
7.4.2.1;III–V Materials;59
7.4.2.2;Graphene Material;61
7.4.2.3;Silicene, Germanene, and Other Similar 2D Materials;65
7.4.2.4;Germanium Material;67
7.5;References;69
8;2 Basics of Integrated Photonics;78
8.1;General;78
8.1.1;Buried Channel Waveguide;81
8.1.2;Strip-Loaded Waveguide;81
8.1.3;Ridge Waveguide;81
8.1.4;Rib Waveguide;81
8.2;Basics of Lasers, Modulators, Detectors, and Wavelength Selective Devices;83
8.2.1;Lasers;83
8.3;Basics Of Photonic Detectors;85
8.4;Detector Characteristics;87
8.5;Responsivity;89
8.6;Dark Current;89
8.7;Noise Characteristics of Photodetectors;89
8.8;Modulators: Principles and Mechanisms of Optical Modulation;91
8.9;Photonics Switches: Spatial Routing of High-Speed Data Streams;94
8.9.1;Switches;94
8.9.2;Devices for Wavelength Division Multiplexed Systems;96
8.9.3;Devices Based on Spectrally Dependent Interference Effects;98
8.10;References;99
9;3 Silicon and Group IV Photonics;102
9.1;Part One: Silicon Photonics Elements for Integrated Photonics;102
9.1.1;General Properties;102
9.1.2;Silicon Photonics Elements for Integrated Photonics: Modulators and Wavelength Selective Devices;104
9.1.2.1;Silicon Electro-Optic Modulators;104
9.1.2.2;Wavelength Selective Devices in Silicon;105
9.1.2.2.1;The Ring Resonator;106
9.2;Part Two: Bandgap Engineering in Group IV Materials for Photonic Application;110
9.3;Part Three: Group IV Photodetectors;115
9.3.1;Integration of Photodiodes with Waveguide or MOSFETs;118
9.3.2;PhotoMOSFETs;119
9.3.3;Group IV-Based Lasers;121
9.4;Part Four: Graphene, New Photonic Material;126
9.4.1;Photodetectors;129
9.5;References;131
10;4 Moore’s Law for Photonics and Electronics;136
10.1;Downscaling of CMOS;136
10.2;Evolution of Logic CMOS Since 1970;139
10.2.1;Prior to NTRS and ITRS Roadmaps;139
10.2.2;After NRTS and ITRS;139
10.2.3;Future of Logic CMOS and Beyond CMOS;140
10.3;Transistor Physical Parameters;140
10.4;Lithography;143
10.5;Strain Engineering and Downscaling;146
10.6;Gate Electrode;147
10.7;Gate Dielectric;148
10.8;Contact Resistance;151
10.9;Substrate Design;152
10.10;Heat Production;153
10.11;Short Channel Effects;154
10.12;Drain-Induced Barrier Lowering;155
10.13;Punch Through;156
10.14;Mobility Degradation;156
10.15;Velocity Saturation;157
10.16;Hot Electron Effect;158
10.17;3D Chips, New Vision for Downscaling;158
10.18;Downscaling for Next 30 Years;159
10.19;Moore’s Law for Integrated Photonics Devices and Some Vision for the Future;160
10.20;References;162
11;5 Complementing Silicon With Other Materials for Light Emission, Efficient Light Modulation and Subwavelength Light Confinement;166
11.1;Part One: Light-Emitting Sources in Si as Photonic Material;166
11.1.1;Rare Earth Metals in Semiconductors;169
11.1.2;Porous Silicon;170
11.2;Part Two: Competing and Complementing Technologies and Materials to an all Group IV-Based Photonics Approach;173
11.2.1;III–V Materials, Plasmonics, and electrooptic polymers (EOPs);173
11.2.1.1;Introduction;173
11.2.1.1.1;Monolithic Integration of III–V Compounds on Silicon;173
11.2.1.1.2;Plasmonics;174
11.2.1.1.3;Electro-Optic Polymers;178
11.3;Authors’ Final Words;180
11.4;References;182

Leseproben

Chapter 2 Basics of Integrated Photonics
In this chapter, the basic of photonic components including different waveguide design, modulators, lasers, and detectors is presented. Keywords
Waveguides; modulators; laser; detectors; general Outline General 63 Buried Channel Waveguide 66 Strip-Loaded Waveguide 66 Ridge Waveguide 66 Rib Waveguide 66 Basics of Lasers, Modulators, Detectors, and Wavelength Selective Devices 68 Lasers 68 Basics of Photonic Detectors 70 Detector Characteristics 72 Responsivity 74 Dark Current 74 Noise Characteristics of Photodetectors 74 Modulators: Principles and Mechanisms of Optical Modulation 76 Photonics Switches: Spatial Routing of High-Speed Data Streams 79 Switches 79 Devices for Wavelength Division Multiplexed Systems 81 Devices Based on Spectrally Dependent Interference Effects 83 References 84 General
Integrated photonics devices, and indeed most photonics systems, include sources (lasers, LEDs), light detectors, and an optical waveguide (or possibly free space) based “fabric” or network in between to transport light in some shape. In the waveguided version, this fabric can include optical modulators, changing amplitude, phase, and/or polarization of the light, as well as switches, to redirect light, optical amplifiers, and wavelength selective structures for filtering, wavelength multiplexing and demultiplexing, and other operations involving wavelengths or light frequency. Integrated photonics has developed at a considerably slower pace than integrated electronics, as a matter of fact, it was a subject of a joke stating that “integrated photonics is the technology of the future and will remain the technology of the future.” However, this state of affairs has altogether been changed by progress in material technology in III–V compounds (GaAs, InP systems, etc), ferroelectrics (LiNbO3), silicon, polymers, and metal optics. The basic structure of an integrated photonics circuit is the optical waveguide (Figure 2.1). In most photonics integration applications and in all such applications where highest performance is sought, these waveguides are single mode, by which is meant that only one spatial mode can propagate, and other modes are evanescent or cut off [1]. However, the waveguides are not strictly single mode and normally support two orthogonal polarizations, a fact that has caused a number of problems in the past and present. The reason is that the standard single mode fiber does not preserve light polarization, and hence photonic elements in a fabric of such fibers need to work independently of the state of polarization of the input light. Such polarization independence normally means that compromises in the device performance have to be made.
Figure 2.1 Schematic diagram of a planar dielectric waveguide in Cartesian coordinate system. nc, nco, and nsub stand for refractive indices of the cover layer, guided wave layer (core), and substrate, respectively. Light is confined in the y direction and generally most of the optical field resides in the core. Light propagation is in the z direction. A so-called channel waveguide confines light in two dimensions (in the so-called core) while it propagates in the third dimension. In the more exotic so-called plasmonic waveguide, light can be guided along a single plasmonic, usually metal-dielectric interface, as will be briefly discussed below. The confinement of light in the two dimensions orthogonal to the direction of light propagation is accomplished by total internal reflection [1], just like in an optical fiber, by having a core with higher refractive index than the surrounding. This surrounding is called cladding in a fiber and is in general partly the substrate in a PIC. Figure 2.2 shows some basic structures of integrated photonic waveguides, with a central core of higher refractive index than the surrounding medium, cladding, or substrate. The optical field is also shown in Figure 2.3.
Figure 2.2 Nonplanar dielectric waveguide types: (a) buried channel, (b) strip-loaded, (c) ridge, and (d) rib.
Figure 2.3 Electric field distribution of Transverse Electric (TE) mode in a silicon channel dielectric waveguide, the Ex(0, y) and Ex(x, 0) curves express the amplitude distribution in x- and y-axis directions, respectively; the substrate material is SiO2, and the cover is air. The guided layer is made of silicon material with the geometry parameters are height=200 nm and width=450 nm. Buried Channel Waveguide
Figure 2.2(a) shows a buried channel waveguide, and it consists of a high-index waveguiding core buried in a low-index cladding. The optical wave can be confined in two dimensions due to differences of refractive index between the core and the cladding. Strip-Loaded Waveguide
Figure 2.2(b) is the geometry of a strip-loaded waveguide, which is composed of three dielectric layers: a substrate, a planar layer, and then a ridge. The planar waveguide (without the strip) already provides optical confinement in the vertical direction (y-axis), and the additional strip can offer localized optical confinement under the strip, due to the local increase of effective refractive index. Ridge Waveguide
Figure 2.2(c) is the ridge waveguide, which is a step-index structure. The difference between dielectric layers at the sides of the guide, as well as the top and bottom faces, can confine the optical wave in two dimensions. Rib Waveguide
Figure 2.2(d) is the cross-section of a rib waveguide. The guiding layer basically consists of a slab with a strip (or several strips) superimposed onto it, which has a similar structure as the strip-loaded waveguide, and the strip is part of the waveguiding core. The waveguides are characterized by the following: • Optical power loss, usually in dB/cm. • Effective index, usually denoted by N or Neff, which is equal to ß/k0, where ß is the real part of the propagation constant and k0 is the wave number in vacuum. The effective index is, for guided waves, larger than cladding index but smaller than core index. • Dispersion, i.e. the variation of the effective index with wavelength. This determines limitations in the propagation length of very short pulses but is normally not so important in PICs due to the small propagation distances. However, for the devices in PICs, such as filters, the so-called group delay dispersion, i.e. the derivative of the group delay with respect to angular frequency can be significant and important. • Geometrical waveguide and optical field cross-sectional area. • The useful wavelength range for light transportation. These are characterized by several “bands” between 1260 and 1675 nm for ICT applications. Waveguide parameters and propagation characteristics for waveguides fabricated with different material compositions are presented in Table 2.1. SOI is silicon on insulator, usually quartz (SiO2). Small waveguide bending radii are desirable for dense integration. Table 2.1 Waveguide Parameters for Different Materials


Index difference ? (%)
=ncore-ncladncore 0.3 0.45 0.75 3.3 7.0 (46) 41 (46) Core size (µm) 8×8 7×7 6×6 3×2 2.5×0.5 (0.2×0.5) 0.2×0.5
0.3×0.3 Loss (dB/cm) <0.01 0.02 0.04 0.1 2.5–3.5 1.8–2.0 Coupling loss (dB/point) <0.1 0.1 0.4 3.7 (2) 5 6.8 (0.8) Waveguide bending radius (mm) 25 15 5 0.8 0.25 (0.005) 0.002–0.005 The waveguides connect different functional elements—lasers, modulators, switches, optical amplifiers, wavelength selective devices, detectors, etc.—and are generally also used to create these device structures, as will be described in the following section. Figure 2.4 shows one of the first publications introducing the concept of integrated photonics.
Figure 2.4 Artists sketch of a monolithic integrated photonics circuit, encompassing single mode waveguides on a planar surface. The waveguides connect the laser source to modulators (see...