Nanoelectronics 101 Mark Lundstrom Purdue University

NCN Nanotechnology 101 Series Nanoelectronics 101 Mark Lundstrom Purdue University Network for Computational Nanotechnology West Lafayette, IN USA 1) Introduction 2) Transistors 3) CMOS 4) Integrated Circuits 5) 21C Electronics? NCN www.nanohub.org 1 1. The importance of transistors (and chips) supercomputers iPods PCs cell phones PDAs 2 1. The scale of things 1 meter 1 millimeter 1 micrometer 1 nanometer (1 billion nm) (1 million nm) (1 thousand nm) • people ants cells molecules things dust (e.g. DNA)3 1. What is a billion? A billion seconds ago it was 1959. A billion minutes ago Jesus was alive. A billion hours ago our ancestors were living in the StoneAge. A billion days ago no-one walked on two feet on earth. 4 1. Vacuum tube electronics Vacuum Tube ENIAC (1945, Mauchly and Echkert, U Penn) http://en.wikipedia.org Edison effect (Edison, 1883) 18,000 vacuum tubes cathode rays (Thompson, 1897) 1000 sq. feet of floor space diode (Fleming, ~1900) 30 tons triode (De Forest, 1906) 150 KW ~50 vacuum tubes / day 5 2. Transistors Field-Effect Transistor Lillienfield, 1925 Heil, 1935 “The transistor was probably the most important invention of the 20th century,” Ira Flatow, Transistorized! www.pbs.org/transistor 6 2. Transistors Sony TR-63 transistors 6-transistor shirt pocket radio 1957 http://www.etedeschi.ndirect.co.uk/early.sony.htm 7 2. Transistors amplifier symbol switch D D D G G G S S S 8 2. Transistors electron energy vs. position E = -q V SDG VD≈ 0V source drain 2 silicon SiO gate electrode VD= VDD gate oxide channel SiO2 9 3. CMOS G G S D S D n+ Si p+ Si p-type silicon n-type silicon n-MOS: VGS > 0 p-MOS: VGS < 0 10 3. CMOS VDD VDD P --> 0 V 1 OUT OUT VIN V 1 0 N VDD VIN--> “transfer characteristic” 11 3. 2-input CMOS NAND gate V AND dd ABC 000 010 P1 P2 100 V 111 outC NAND VA N1 in1 ABC 001 011 VB N2 in2 101 110 12 4. Integrated circuits integrated circuit Intel 4004 Kilby and Noyce (1958, 1959) Hoff and Faggin (1971) ~2200 transistors 13 4. Microelectronics Silicon wafer (300 mm) Silicon “chip” (~ 2 cm x 2 cm) MPU ROM DSP Control logic RAM analog Intel TI cell phone chip 14 4. What if a chip were the size of New York City? MPU ROM 20 km 2 cm DSP Control logic RAM analog • Transistor gate length would be 4 cm. • Feature edges would would be specified to the nearest mm. • There would be 200,000 km of wires (total) on the 8 levels of metal. 15 From Bob Doering, Texas Instruments, Jan. 2004 4. Moore’s Law Gordon E. Moore Co-founder, Intel Corporation Electronics, vol. 38, Copyright © 2005 Intel Corporation. April 19,1965 16 4. Moore’s Law more transistors per chip means: higher performance / lower cost 17 4. Transistor scaling 35 nm 1.2 nm ~ L Each technology generation: (device scaling) L → L 2 A → A 2 Number of transistors per chip doubles (Moore’s Law) 18 4. Nanoelectronics Working at the length scale of 1-100 nm in order to create materials, devices, and systems with fundamentally new properties and functions because of their nanoscale size. paraphrased from www.nano.gov 19 4. Transistor scaling 35 nm 1.2 nm ~ L Each technology generation: (device scaling) L → L 2 A → A 2 Number of transistors per chip doubles (Moore’s Law) 20 4. Scaling challenges ~ L 1) low voltage operation 2) high on-current 3) low off-current 4) series resistance 5) device variability 21 4. More than Transistors Metal 7 Metal 6 Metal 5 Metal 4 Metal 3 Metal 2 Metal 1 transistor Silicon wafer 22 4. The power crises RR Power density will increase 10000 Rocket Nozzle 1000 Nuclear Reactor 100 8086 10 4004 Hot Plate P6 8008 8085 386 Pentiumｨ proc 286 486 Power Density (W/cm2) Power Density 8080 1 1970 1980 1990 2000 2010 Year ｨ 14 23 4. Design challenges 1) power 2) interconnects 3) device variability 4) reliability 5) complexity 24 4. Exponential Growth 1 90 nm 1B/chip 2 2B 3 4B 4 8B 5 16B 6 32B 7 64B 8 128B 10 256B 11 512B 12 1T 25 4. Exponential Growth #1 1 grain of rice d d d d #18 d d d d small wastebasket #37 d d d d entire room #27 large table #64 1019 grains surface of Earth from “Digital Immortal,” by R.W. Lucky, New Republic, Nov. 8. 1999 26 4. Exponential Growth #1 First IC (1959) d d d d d d d d d d d 32d 27 5. Beyone Silicon CMOS: Molecular electronics? STM C60 on Si(100) 2x1 TEMPO on p+-Si(100) 3.0 1.5 Shoulder 0.0 -1.5 Current (nA) NDR -3.0 -5.0 -2.5 0.0 2.5 5.0 Voltage (V) (Liang and Ghosh) Hersam, Datta, Purdue 28 5. Beyond Silicon CMOS: Molecular transistors? S. Datta, A. Ghosh, P. Damle, T. Rakshit Ghosh, Rakshit, Datta, Nanoletters 4, 565, 2004 29 5. Beyond Silicon CMOS: Carbon nanotube transistors? Al Gate HfO2 D S 10 nm SiO2 p++ Si SWNT DSG Hongjie Dai group, Stanford McEuen et al., IEEE Trans. Nanotech., 1 , 78, 2002. 30 5. Beyond Silicon CMOS: Nanowire transistors? Samuelson Group Lund 31 5. Beyond transistors? Gate N S D spinFET qubit S + spin quantum computing 32 5. 21st Century Electronics 1) CMOS devices face serious challenges leakage, variations, interconnects, … 2) Power dissipation limits device density not our ability to make devices small 3) CMOS will operate near ultimate limits no transistor can be fundamentally better 4) CMOS will provide more devices than can be used increasingly, design will drive progress 33 5. 21st Century Electronics 5) New tools, assembly techniques, and understanding will help push CMOS to its limits 6) Beyond CMOS devices will add functionality to CMOS non-volatile memory, opto-electronics, sensing…. 7) Beyond CMOS technology will address new markets macroelectronics, bio-medical devices, … 8) Biology may provide inspiration for new technologies bottom-up assembly, human intelligence 34 Nanoelectronics 101 Questions? 35.

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