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  1. 1. Introduction to VLSI
  2. 2. <ul><li>• CADtool: Computer Aided design </li></ul><ul><li>• TCADtool: Technology Computer Aided Design offers a comprehensive suite of products that includes the industry leading process and device simulation tools, as well as a powerful simulation environment for managing simulation tasks and analyzing simulation results </li></ul>
  3. 3. <ul><li>• IC: Integrated circuits: many transistors on one chip. </li></ul><ul><li>• Very Large Scale Integration (VLSI): very many </li></ul><ul><li>• CMOS :Complementary Metal Oxide Semiconductor </li></ul><ul><li>– Fast, cheap, low power transistors </li></ul><ul><li>• Today: How to build your own simple CMOS chip (you can have your own company) </li></ul><ul><li>– CMOS transistors: control performance </li></ul><ul><li>– Building logic gates from transistors (AND, OR, NOT, XOR) </li></ul><ul><li>– Amplifier, adder, Flip Flop System level design: </li></ul><ul><li>– Transistor layoutand fabrication </li></ul>
  4. 4. <ul><li>1958: First integrated circuit–Flip-flop using two transistors </li></ul><ul><li>Built by Jack Kilby at Texas Instruments </li></ul><ul><li>2003–Intel Pentium 4 mprocessor (55 million transistors) </li></ul><ul><li>– 512 Mbit DRAM (> 0.5 billion transistors) </li></ul><ul><li>53% compound annual growth rate over 45 years </li></ul><ul><li>– No other technology has grown so fast so long• </li></ul><ul><li>--Driven by miniaturization of transistors–Smaller is cheaper, faster, lower in power! </li></ul>
  5. 5. <ul><li>•1018 transistors manufactured in 2003–100 million for every human on the planet05010015020019821984198619881990199219941996199820002002 </li></ul>
  6. 7. <ul><li>• Integration:Levels </li></ul><ul><li>• SSI:10gates/ chip: Small signal integration </li></ul><ul><li>• MSI:1000gates/ chip: Medium Signal Integration </li></ul><ul><li>• LSI:10,000 gates/chip: Large Signal Integration </li></ul><ul><li>• VLSI:higher that 10K gates/ chips </li></ul>
  7. 9. <ul><li>• In 1971, minimum dimensions of 10 um in 4004 </li></ul><ul><li>• In 2003, minimum dimensions of .18um in Pentium4. </li></ul><ul><li>• Scaling down forever ? (No, transistors cannot be less than atoms) </li></ul><ul><li>• Many predictions of fundamental limits to scaling have already proven wrong </li></ul><ul><li>• We believe that scaling will continue for at least another decade. </li></ul><ul><li>• What is the future? </li></ul>
  8. 12. <ul><li>• Silicon is a semiconductor </li></ul><ul><li>• Pure silicon has no free carriers and conducts poorly </li></ul><ul><li>• Adding dopants increases the conductivity </li></ul><ul><li>• Group V(Arsenic): extra electron (n-type) </li></ul><ul><li>• Group III(Boron): missing electron, called hole (p-type) </li></ul>
  9. 15. <ul><li>•Four terminals: gate, source, drain, body </li></ul><ul><li>•Gate –oxide –body stack looks like a capacitor </li></ul><ul><li>–Gate and body are conductors </li></ul><ul><li>–SiO2(oxide) is a very good insulator </li></ul><ul><li>–Called metal –oxide –semiconductor (MOS) capacitor </li></ul><ul><li>–Even though gate is no longer made of metal </li></ul>
  10. 17. <ul><li>•Body is commonly tied to ground (0 V) </li></ul><ul><li>•When the gate is at a low voltage: </li></ul><ul><li>–P-type body is at low voltage (substrate)–Source-body and drain-body diodes are OFF </li></ul><ul><li>–No current flows, transistor is OFF </li></ul>
  11. 19. <ul><li>•When the gate is at a high voltage: </li></ul><ul><li>–Positive charge on gate of MOS capacitor </li></ul><ul><li>–Negative charge attracted to body </li></ul><ul><li>–Inverts a channel under gate to n-type </li></ul><ul><li>–Now current can flow through n-type silicon from source through channel to drain, transistor is ON </li></ul>
  12. 21. <ul><li>•Similar, but doping and voltages reversed </li></ul><ul><li>–Body tied to high voltage (VDD) </li></ul><ul><li>–Gate low: transistor ON </li></ul><ul><li>–Gate high: transistor OFF–Bubble indicates inverted behavior </li></ul>
  13. 22. <ul><li>Power Supply </li></ul><ul><li>• GND = 0 V </li></ul><ul><li>• In 1980’s, VDD= 5V </li></ul><ul><li>• VDD has decreased in modern processes –High VDD would damage modern tiny transistors </li></ul><ul><li>– Lower VDDsaves power </li></ul><ul><li>• VDD= 3.3, 2.5, 1.8, 1.5, 1.2, 1.0, </li></ul><ul><li>• Dimension of the transistors decrease. </li></ul>
  14. 27. <ul><li>• Gate delay/ Propagation delays </li></ul><ul><li>• Rise Time </li></ul><ul><li>• Fall Time </li></ul><ul><li>--control the performance of the gate/ system </li></ul><ul><li>• Fast/ slow/Loading effect </li></ul><ul><li>• BiCMOS: Bipolar CMOS (Faster low power loss) </li></ul>