Department of Electronics Nanoelectronics 01 Atsufumi Hirohata Department of Electronics 13:00 Monday, 16/January/2017 (P/T 006)

Go into Nano-Scale 10 -3 Micron-scale Lateral Size [m] 10 -6 Vacuum tube (~ 20 cm) † † http://www.wikipedia.org/ Transistor (~ 1 cm) ‡ ‡ S. M. Sze, Physics of Semiconductor Devices (John Wiley, New York, 1981). 10 -3 Cassette tape (~ 600 µm) Human hair (~ 50 µm) Transistor (~ 50 µm) † Video cassette tape (~ 19 µm) Micron-scale * http://www.esa.int/esaKIDSen/SEMOC68LURE_LifeinSpace_1.html Red blood cell (~ 7 µm) * Floppy disc (~ 1.5  190 µm) Lateral Size [m] 10 -6 MO disc (~ 290  1000 nm) Sub-Micron-scale Processor ‡ (~ 45 nm) ** http://www.guardian.co.uk/pictures/image/0,8543,-11404142447,00.html Virus (~ 80 nm) ** HDD (~ 25  200 nm) Nano-scale DNA (width ~ 2 nm) *** *** http://www.wired.com/medtech/health/news/2003/02/57674 Carbon nano-tube (width ~ 1 nm) 10 -9 Quantum-scale Hydrogen atom (~ 0.1 nm)

Nanoelectronics Electronics Materials Science Electron transport Semiconductors Magnetism Ferromagnets Superconductors Organic materials In conclusion, we observed efficient spin filtering in Schottky diodes at room temperature. This depends on the orientation of the photon helicity and the FM magnetization. Using spin valve structures, we demonstrated that spin filtering occurs in ballistic regions. Combining these results, ballistic spin filtering was achieved at room temperature. Physics Electromagnetism Quantum mechanics

Contents of Nanoelectronics Lectures : Atsufumi Hirohata (atsufumi.hirohata@york.ac.uk, P/Z 019) Electrical transport in nano-scale (Weeks 2 ~ 10) [13:00 Mons. (P/T 006) & 11:00 Weds. (D/L 036)] I. Introduction to nanoelectronics (01) II. Electromagnetism (02 & 03) III. Basics of quantum mechanics (04 ~ 06) IV. Application of quantum mechanics (07, 10, 11, 13 & 14) V. Nanodevices (08, 09, 12, 15 ~ 18) Workshops : (1/2 marks in your assessment) Equation solving in quantum physics (Week 2, 4, 6 & 8) [17:00 Fris. (V 123 & P/T 007)] Submit your answers to the General Office by 12:00 on the following Fris. Examination : (1/2 marks in your assessment) Closed book exam (Equation solving + Essay)

References General textbooks in nanoelectronics : K. Goser, P. Glosekotter and J. Diestuhl, Nanoelectronics and Nanosystems (Springer, Berlin, 2004). covers all the topics in the field. V. V. Mitin, V. A. Kochelap and M. A. Stroscio, Introduction to Nanoelectronics (Cambridge University Press, Cambridge, 2008). focuses on semiconductor nanoelectronics and nanodevices. Douglas Natelson, Nanostructures and Nanotechnology (Cambridge University Press, Cambridge, 2016). focueses on nanoelectronic devices. General textbooks in quantum mechanics : R. Eisberg and R. Resnick, Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles (John Wiley, New York, 1985). G. L. Squires, Problems in Quantum Mechanics (Cambridge University Press, Cambridge, 1995). provides broad problems with solutions. Lecture notes / slides : http://www-users.york.ac.uk/~ah566/lectures/lectures.html

01 Micro- to Nano-Electronics ? Device miniaturisation Micron / nanometre Nanofabrication New functionality Electron transport

Miniaturisation of Data Processors * http://www.wikipedia.org/

Miniaturisation and Integration in Semiconductor Devices Moore’s law : “The number of transistors on a chip will double every 18 months.” (1965) 10 years later he revised this to “every 24 months.”  The development speed becomes even faster ! * http://www.intel.com/

Current Semiconductor Technology 45-nm rule : Nanofabrication method : 0.9 nm thick * http://www.intel.com/ ** http://www.kodak.com/

Roadmap for Si-Based Devices * V. V. Mitin, V. A. Kochelap and M. A. Stroscio, Introduction to Nanoelectronics (Cambridge University Press, Cambridge, 2008).

Latest Chips

Cross-Section of Latest Chips

Advantages of Latest Chips

Improvements by Latest Chips

Increase in Recording Density of Hard Disc Drives Similar to Moore’s law : Areal density in a hard disc drive (HDD) will double every 36 months. (~ 1992) After giant magnetoresistance (GMR) implementation, it will double less than every 20 months. (1992 ~)

How Does a Recording Head Look Like ? Recording media … Recording head … Read / write head Lubricant ~ 1 nm Carbon coating < 15 nm Magnetic media ~ 30 nm Chromium buffer ~ 50 nm Nickel buffer ~ 10 m Metalic/glass substrate Arm Recording head Disc rotation Configurations of a platter : If the head is a jumbo jet (B747)... Height 1.5 mm 0.15 mm 0.5 mm 1 mm N S

Development of a HDD Recording density increases at 100% / year : First HDD in the world : 　RAMMAC 305 (1956, IBM) 　60 cm platter × 50 = 4.4 MB 　10 Mbit / inch2 Current HDD : 　MK2035GSS (2006, Toshiba) 　6.4 cm platter × 2 = 200 GB 　178.8 Gbit / inch2 × 18,000

Current Magnetic Recording Technology Anisotropic to Giant magnetoresistance : Longitudinal to perpendicular recording : * http://www.hitachigst.com/

Miniaturisation in Magnetic Recording Technology Size evolution of a recording head in a HDD :

Advancement in Communication Technologies Similar to Moore’s law : Data transfer becomes faster. LAN Inside a PC Network

Advantages of Nano-Scale Miniaturisation From microelectronics to nanoelectronics : Reduction of effective electron paths Reduction of electron scattering Decrease in an acceleration voltage Decrease in device size Faster operation Lower power consumption Higher integration / lower cost More complicated fabrication processes Higher fabrication cost Larger distributions in device properties Leakage currents (insulator < 1nm thick) No electron confinement (path < 10 nm thick) Joule heating Need to be solved in Nanoelectronics Electromagnetism Quantum physics Nano-device fabrication

Electron Transport in a Nano-Device Diffusive transport : Ballistic transport : Electron scattering  Electrical resistivity Negligible electron scattering  Negligible electrical resistivity  Transport in a vacuum W > F W ~ F L ~ L > : electron mean free path (~ 40 nm for Cu @ RT) F : Fermi wave length (~ 1 nm) Hot-electron

Electron Transport in Nano-Structures 4 fundamental nano-device structures : 2D Ultrathin film (quantum well) Superlattice (multilayer) 1D 0D Quantum wire (nano-wire) Quantum dot (nano-dot) * H. Sakaki and N. Yokoyama, Nanoelectronics (Ohm-sha, Tokyo, 2004).