footer.jpg pic_titel_1.jpg Is Silicon Age Coming to an End…? Claudiu V. Falub Laboratory for Solid State Physics ETH Zürich, Switzerland cfalub@phys.ethz.ch 5 December 2012 Masaryk University, Brno eth_ologo footer.jpg 2 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno footer.jpg 3 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno footer.jpg 4 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno footer.jpg 5 Claudiu V. Falub, ETH Zürich c:\Users\Claudiu\Documents\Work-ETHZ\Logos\eth_logo_black.png http://www.3cx.de/blog/wp-content/uploads/2010/04/swissflag.gif Laboratory for Solid State Physics Thomas Kreiliger Alfonso G. Taboada Elisabeth Müller Hans von Känel Claudiu V. Falub Frontiers In Research: Space and Time 860 m2 Physics of New Materials http://www.pnm.ethz.ch 5 December 2012, Brno footer.jpg 6 Claudiu V. Falub, ETH Zürich http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1913/werner_postcard.jpg http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1915/willstatter.jpg http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1918/haber.jpg http://www.nobelprize.org/nobel_prizes/physics/laureates/1920/guillaume.jpg http://sureshemre.files.wordpress.com/2011/12/albert_einstein_nobel.png http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1936/debye.jpg http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1938/kuhn.jpg http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1939/butenandt.jpg http://www.nobelprize.org/nobel_prizes/physics/laureates/1943/stern.jpg http://www.nobelprize.org/nobel_prizes/physics/laureates/1945/pauli.jpg http://www.nobelprize.org/nobel_prizes/medicine/laureates/1950/reichstein.jpg https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcS_UF9zbsat5LKN9wUD3ZbPkBJilljLKKaviF9CVsoxm1Y DHVFgHw https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTI1hYMiLvdsA3-WrpvLID_u-As4jNOdZietukjUH_Fz36 c1NmaEA http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1975/prelog.jpg https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSiqxf-GlyyPjo3uS23uvF5TLMs8_kJ6Ct8yceK1h64F3v 9KB_ZPQ https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRTrtpy0g8QxSpAwHvwUx8CR14W5POLIyUhHqx5lPPR1-E yxCja7w https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTFdKXmoBbxbG97WdS4uSPblu3ZZubi8qBgUYYj_IAHv3q 4dzkz2g J. Georg Bednorz https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTZ5hSkygJ9mEUqmrp0ieh9b2QLyG52wlyW8N9Drcj7jD8 NSxCi https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSFJj3mGu7l9zGg-5QpiHqfGzrNS7IfdvqRCN42NRFoNkb RvxLJUQ https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcRbWrYQ1CMcI66_ssJndDvIrgci_kXCGf23hQCRcwSFY4P M6i3_4g W.K. Röntgen Physics 1901 A. Werner Chemistry 1913 R. Willstätter Chemistry 1915 F. Haber Chemistry 1918 C.-E. Guillame Physics 1918 A. Einstein Physics 1921 P. Debye Chemistry 1936 R. Kuhn Chemistry 1938 L. Ruzicka Chemistry 1938 O. Stern Physics 1943 W. Pauli Physics 1945 T. Reichstein Medicine 1950 F. Bloch Physics 1952 H. Staundinger Chemistry 1953 V. Prelog Chemistry 1975 W. Arber Medicine 1978 H. Rohrer Physics 1986 G. Bednorz Physics 1987 A. Müller Physics 1987 R. Ernst Chemistry 1991 K. Wüthrich Chemistry 2002 21 Nobel Prize Laureates of ETH Zürich 10 Chemistry, 9 Physics, 2 Medicine 5 December 2012, Brno footer.jpg NEW MATERIALS Þ key to technological “quantum leaps” Stone Iron Bronze Silicon http://windows7themer.com/wp-content/uploads/2012/07/Plasma-Windows-7-Logon-Screen.png 7 http://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/NASA_Mars_Rover.jpg/300px-NASA_Mars_Rover. jpg C:\Users\Claudiu\Documents\Work-ETHZ\Publications\ETHZ\CAS2012\silicon-5.jpg C:\Users\Claudiu\Documents\Work-ETHZ\Publications\ETHZ\CAS2012\images_5Ccomputerscience_5Cmain1.jpg The Age of Silicon Cover image expansion Claudiu V. Falub, ETH Zürich 5 December 2012, Brno footer.jpg 8 Why Silicon? Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Si 14 28 Ø abundant Ø cheap Ø amazing mechanical, chemical and electronical properties Ø well-known to mankind (SiO2: sand, glass) footer.jpg 9 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Crystal Structures Wurtzite Structure (GaN, AlN, CdS, BN, etc.) Diamond Structure (Si, Ge) Zincblende Structure (GaAs, InP, GaP, etc. ) footer.jpg 10 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Tetrahedrally Bonded Semiconductors Nitrides2b footer.jpg 11 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno From Atomic Levels to Band Structures crystal lattice spacing 4N states 4N electrons Valence band 4N states 0 electrons Conduction band 0 states Eg Z=14: 1s22s22p63s23p2 footer.jpg 12 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno overlap Conduction band Valence band Fermi level METAL SEMICONDUCTOR INSULATOR From Band Structures to Different Materials footer.jpg 13 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Semiconductor Doping Electrons in CB (mobile) Holes in VB (mobile) Positive ions (immobile donors) Negative ions (immobile acceptors) CB VB n-type semiconductor p-type semiconductor footer.jpg 14 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Transistor Effect C:\Users\Claudiu\Desktop\Brno\PPT\Bardeen_Shockley_Brattain_1948.JPG nMOSFET Nobel: 1956 Ge Transistor iD vDS vGS increases saturation linear footer.jpg 15 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno From Transistor to CMOS Devices footer.jpg Moore's Law: “Transistor density doubles every 18 months.” 16 Claudiu V. Falub, ETH Zürich · More computing power · Less power consumption · Less heat dissipation 800 nm (1989) 90 nm (2002) 65 nm (2006) 45 nm (2008) 22 nm (2010) 14 nm (2013) 11 nm (2015) 6 nm (2018) 4 nm (2022) Graphene M. Kako “Moore’s law will collapse“ K. Novoselov Extending Moore’s Law beyond Silicon Spintronics A. Geim Breaking Moore’s Law (2012) BREAKTHROUGH Atomic Devices SCIENCE 335, 64 (2012) "Ohm’s law survives to the Atomic Scale" BREAKTHROUGH Length (L) Ohm’s law Coherent 5 December 2012, Brno A. Fert P. Grünberg (2012) BREAKTHROUGH Nature Phys. 8, 757 (2012) footer.jpg BREAKTHROUGHS 17 Claudiu V. Falub, ETH Zürich Nanowires in Nanoelectronics SCIENCE 319, 579 (2008) Silicon Photonics 50 Gbps Silicon Photonic Link (2010) 5 December 2012, Brno Strained Silicon (90 ® 32 nm ) 3D Tri-gate Transistors (22 nm ) footer.jpg 18 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Strained Silicon Biaxial Uniaxial Si Si SiGe http://www.legitreviews.com/images/reviews/103/silicon.jpg footer.jpg 19 Claudiu V. Falub, ETH Zürich International Roadmap for Semiconductors 5 December 2012, Brno “The integrated silicon chip or system-on-a-chip of the future” footer.jpg 20 Claudiu V. Falub, ETH Zürich Extending Moore’s Law beyond Silicon C:\Users\Claudiu\Documents\Work-ETHZ\Publications\ETHZ\CAS2012\opinion_cybernaut1.jpg Extending Si technology to other semiconducting materials with optical and electrical properties beyond Si. 5 December 2012, Brno footer.jpg 21 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno From Microelectronics to Optoelectronics Ge Si Eg (Si) = 1.12 eV Eg (Ge) = 0.664 eV phonon phonon Indirect bandgap semiconductor C:\work\talks\3.tif GaAs Direct bandgap semiconductor Si: Inefficient at emitting light (interband transitions involve momentum transfer, i.e., the heat-generating process for electron-hole recombination dominates) footer.jpg 22 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Squeeze Light out of Silicon Ø Ge-dots Ø Er-doped Si Ø Short period superlattices Ø Porous Si Ø Si nanocrystals Ø Strained Si Interband Intersubband Ø Quantum Cascade Laser (QCL) “A silicon laser would revolutionize telecommunications, electronics and computing. Squeezing light out of silicon is no easy task, but researchers are becoming more optimistic about its light-emitting abilities.“ Nature 409, 974 - 976 (2001) footer.jpg 23 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Interband vs. Intersubband Transitions footer.jpg 24 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Quantum Cascade Laser (QCL) Cascade: Multiple repetition of active region Multiple photons from one electron Design for III-V compounds (InGaAs/InAlAs: J. Faist et al., Science 264, 533 (1994). Theoretical prediction: R.F. Kazarinov and R.A. Suris, Fiz. Tekh. Poluvrodvn. 5, 797-800 (1971) footer.jpg 25 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Uv-LED Interband Lasers (GaN, InGaAs, GaAs/AlGaAs, etc.) OPTO 0.4 mm 1 m m 10 m m vislight UV IR Atmospheric window (8-12 m m) Visible spectrum NH3 8.495 m m H2O 8.513 mm CO2 15 mm Quantum Cascade Lasers (InGaAs/AlInAs, GaAs/AlGaAs) with III-V ELECTRONICS Silicon Possible (nature of the bandgap irrelevant) with Si Not possible (indirect bandgap material) III-V material Bridging Optoelectronics and Microelectronics footer.jpg 26 Monolithic Integration (Hetero-Epitaxy) Substrate Layer 1 Layer 2 Processed wafer Claudiu V. Falub, ETH Zürich 5 December 2012, Brno footer.jpg 27 Molecular Beam Epitaxy (MBE) Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Schematic diagram of a MBE system C:\work\talks\images\growth.tif Requirements: Ø Many (> 1000) few-atoms thick layers of alloy materials Ø Atomic control of layer thickness Ø Atomically flat layer interfaces ~ 40 nm 28 Si and SiGe layers Ø Typical growth rates (~Å/s) footer.jpg 28 Molecular Beam Epitaxy (MBE) Claudiu V. Falub, ETH Zürich 5 December 2012, Brno U:\quelle.tif C:\work\talks\images\wafer.tif C:\work\talks\images\ebeam.tif Growth chamber Wafer holder Electron beam evaporation Si and Ge sources Heater Solid Si e-beam footer.jpg 29 Low-Energy Plasma Enhanced Chemical Vapor Deposition Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Ge H H H + Si + H H Ar + Ar Ar Ar Ar Ge H H H H Si H H H H Ar Ar Ar Ar Ar Si Ge Ge Si Si Si Ge Principle of low-energy plasma-enhanced CVD: High-current low-voltage arc discharge SiH4 and GeH4 are transformed into highly reactive radicals Very high growth rates (0.5 µm/min) possible at low substrate temperatures footer.jpg 30 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Characterization of Epitaxial Structures §Structural: §Reflection high energy electron diffraction (RHEED) §Optical reflection spectroscopy §X-ray diffraction §Transmission electron microscopy §Secondary ion mass spectrometry (SIMS) §Rutherford backscattering spectrometry (RBS) §Scanning Tunneling Microscopy §Atomic Force Microscopy §Optical: §Reflection & transmission §Photoluminescence §Raman scattering §Electrical: §Conductivity & Hall effect § § footer.jpg 31 Reflective High Energy Electron Diffraction (RHEED) Claudiu V. Falub, ETH Zürich 5 December 2012, Brno E=10-30 keV, w=1-4° (depth sensitivity ~1nm) http://www.material.tohoku.ac.jp/%7Ekaimenb/Figs/RHEED2.gif http://www.material.tohoku.ac.jp/%7Ekaimenb/Figs/RHEED2.gif (Kikuchi lines) Time Incident electron beam along <11-2> azimuth RHEED Pattern of Si(111)-7x7 footer.jpg 32 High-Resolution X-Ray Diffraction (HRXRD) Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Qx Qz Q relaxed Si1-xGex bulk Si Misfit Strained SiGe on Si substrate Relaxed SiGe on Si substrate strained Si1-xGex bulk Si a┴ a║ a┴ a║ 2p/l 4p/l 2p/l (224) (001) 20 nm Si50Ge50 200 nm Si50Ge50 Si Si50Ge50 Truncation rod Diffuse scattering 69.1° 004 a┴ Si(004) Si(004) Si50Ge50 a┴ a║ Si(224) 88.0° a║ Si(224) Si50Ge50 224 footer.jpg 33 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Motivation: Integrated Miniaturized X-ray Systems §Next Generation X-Ray Systems §High resolution/sensitivity §Ge as conversion layer §No bump-bonding (monolithic integration) “NEXRAY” Fast, programmable X-ray sources Ge layers for high-energy X-ray detection Single-photon solid-state X-ray detection Phase contrast X-ray imaging logo_empa_bl_ol [Converti] c:\Users\Claudiu\Documents\Work-ETHZ\Logos\eth_logo_black.png CSEM-regular http://www.nanotera.ch/images/mainlogo.gif footer.jpg 34 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Motivation: Next Generation X-Ray Detectors 64´64 pixel IR sensor with integrated Ge photodiodes D = 100 mm For X-rays → SUPER THICK (> 50 mm !!!) high quality (i.e. dislocations, uniformity) Ge epilayers · Why Germanium? 2 mm · Monolithic integration of a 3 mm Ge film with CMOS for IR radiation was demonstrated at ETHZ/CSEM R. Kaufmann et al., J. Appl. Phys. 110, 023107 (2011) Ge Z=32 Si Z=14 footer.jpg 35 Key Problems of Hetero-Epitaxy exhibit_3.gif exhibit_3.gif exhibit_3.gif a=asub a>asub aa0 a0 a0 MDs TDs a1>a0 TDs – threading dislocations MDs – misfit dislocations Untitled-2 200 nm Ge TDs MDs Claudiu V. Falub, ETH Zürich 5 December 2012, Brno footer.jpg 36 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno C:\Users\Claudiu\Documents\Work-ETHZ\Science\Science\SciPak\3.jpg footer.jpg 37 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno To Be Continued… footer.jpg 38 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno Conclusions ØSilicon age has still got tremendous potential for further progress Þ its end is not near, yet! ØMoore’s law may eventually no longer decide the pace of microelectronics progress. Ø“More than Moore” will be the new driving force. footer.jpg 39 Claudiu V. Falub, ETH Zürich 5 December 2012, Brno C:\Users\Claudiu\Pictures\Nepal\15.jpg Thank you for your attention ! Khumjung, Himalaya, Nepal, November 2003