2. Keeping Up with Moore’s Law

3. Who the heck is this Moore guy anyway? Gordon E. Moore was the cofounder of Intel Corporation Gordon E. Moore was the cofounder of Intel Corporation Earned a B.S. in Chemistry from the University of California at Berkeley and a Ph.D. in Chemistry and Physics Earned a B.S. in Chemistry from the University of California at Berkeley and a Ph.D. in Chemistry and Physics

4. And his law? Moore’s Law states that every 18 months, the number of devices on a microchip (and hence the potential power of a computer) that can be squeezed on to a single chip is doubled Moore’s Law states that every 18 months, the number of devices on a microchip (and hence the potential power of a computer) that can be squeezed on to a single chip is doubled This was proposed in 1965 and still holds true today!!!! This was proposed in 1965 and still holds true today!!!!

5. Integrated Circuits Three basic components of integrated circuits are transistors and DRAM (dynamic random access memory) and interconnects Three basic components of integrated circuits are transistors and DRAM (dynamic random access memory) and interconnects The industry is trying to simultaneously scale down these components so more can be fit onto a chip The industry is trying to simultaneously scale down these components so more can be fit onto a chip

6. Transistors: Doping silicon (it’s not what you think) Doping is adding atoms to a material to change its electronic properties Doping is adding atoms to a material to change its electronic properties N-type silicon (phosphorous doped) contains free electrons N-type silicon (phosphorous doped) contains free electrons P-type silicon (boron doped) contains free “holes” P-type silicon (boron doped) contains free “holes”

7. What’s a Transistor? Transistors are composed of n-type and p-type silicon Made up of a source, gate, and drain The distance between the source and the drain is called the feature size. Insulator (gate dielectric) placed between gate and p- type silicon.

8. Problems with reducing transistor size In scaling, the thickness of the gate dielectric must decrease as the gate length decreases (feature size). In scaling, the thickness of the gate dielectric must decrease as the gate length decreases (feature size). Currently gates sizes are around 2nm and are projected to decrease to 0.5nm. (~2 atomic layers) Currently gates sizes are around 2nm and are projected to decrease to 0.5nm. (~2 atomic layers) Tunneling induced leakage becomes a problem. Tunneling induced leakage becomes a problem.

9. Solutions? Thicker high dielectric insulators Thicker high dielectric insulators Reinvent the transistor: Reinvent the transistor: Single-electron transistor (SET) (basis for quantum computers) Single-electron transistor (SET) (basis for quantum computers) Use carbon nanotubes to conduct the charge Use carbon nanotubes to conduct the charge Organic compounds Organic compounds

10. What’s DRAM? Essentially a capacitor that stores charge Essentially a capacitor that stores charge When charge is present, the binary representation is 1 (the charge often leaks from the capacitor necessitating a periodic refresh) When charge is present, the binary representation is 1 (the charge often leaks from the capacitor necessitating a periodic refresh) When charge is not present, the binary representation is 0 When charge is not present, the binary representation is 0

11. And how can we make it smaller than ~22μm 2 ? By reducing the area of the capacitor, of course! By reducing the area of the capacitor, of course! Since the charge remains constant, the thickness of the silicon dioxide dielectric must be reduced (bc capaticence is proportional to the dielectric area but inversely proportional to the thickness) Since the charge remains constant, the thickness of the silicon dioxide dielectric must be reduced (bc capaticence is proportional to the dielectric area but inversely proportional to the thickness) The thickness has become so small that quantum tunneling causes the charge to leak faster than DRAM refresh rates The thickness has become so small that quantum tunneling causes the charge to leak faster than DRAM refresh rates

12. Solutions? Find an insulator with a higher dielectric constant Find an insulator with a higher dielectric constant Change the device geometry, structure, and process Change the device geometry, structure, and process

13. Interconnects Links components of the integrated circuit Links components of the integrated circuit Uses 70% of the chip’s area Uses 70% of the chip’s area Copper wiring is mainly used (but it can only be scaled down so far) Copper wiring is mainly used (but it can only be scaled down so far) Will limit processing speed even if reductions in transistor size occur Will limit processing speed even if reductions in transistor size occur

14. Developing technologies for faster interconnects Wireless interconnects (radio-frequency signals) Wireless interconnects (radio-frequency signals) Optical interconnects Optical interconnects Use high vertical cavity-surface-emitting lasers (VCSELs) to generate light and build waveguides on the chip Use high vertical cavity-surface-emitting lasers (VCSELs) to generate light and build waveguides on the chip Use light from external sources and use reflectors to direct them Use light from external sources and use reflectors to direct them

15. Chip making With the reduction of the size of IC components, resolution in making them must increase With the reduction of the size of IC components, resolution in making them must increase Limitations in lithography (method used to make chips) are economic (don’t know how to print smaller components cost-effectively) Limitations in lithography (method used to make chips) are economic (don’t know how to print smaller components cost-effectively) Research is primarily concerned with high volume production of these nano components Research is primarily concerned with high volume production of these nano components

16. How the darn thing works (pattern lithography) The wafer is first covered by a photoresist The light that passes throught the photomask changes chemical structure of the photoresist and that part can be washed away The resulting pattern is then exposed to doping, deposition, or etching. The rest of the photoresist is then removed after a permanent change in the wafer is made.

17. Types of lithography Optical Optical Electron beam Electron beam Proximity X-ray Proximity X-ray Extreme ultraviolet Extreme ultraviolet

18. So…who’s tired of me talking? Well, it’s almost over. Well, it’s almost over.

19. To sum it all up Traditional scaling of integrated circuits is coming to an end (materials must change) Traditional scaling of integrated circuits is coming to an end (materials must change) Quantum physics is becoming more significant in the quest for more computing power Quantum physics is becoming more significant in the quest for more computing power

20. The International Technological Roadmap for Semiconductors (ITRS) Developed by the Semiconductor Industry Association in ‘99, it outlines the advances of the industry til ’14 Developed by the Semiconductor Industry Association in ‘99, it outlines the advances of the industry til ’14 To give you an idea by then feature lengths will be ~20nm, gate thicknesses will be ~0.5nm, and roughly 4 electrons would be required to switch on or off a transistor (as opposed to ~1000 electrons today) To give you an idea by then feature lengths will be ~20nm, gate thicknesses will be ~0.5nm, and roughly 4 electrons would be required to switch on or off a transistor (as opposed to ~1000 electrons today)

21. So, Moore’s Law is going to always hold, right? Wrong Wrong Since computing is a physical system, it must abide by limits set by the laws of physics Since computing is a physical system, it must abide by limits set by the laws of physics Seth Lloyd of MIT actually computed the physical limits of computing using quantum mechanics (however, we won’t be able to approach these limits because his calculations are based on very simplistic “perfect” computers) Seth Lloyd of MIT actually computed the physical limits of computing using quantum mechanics (however, we won’t be able to approach these limits because his calculations are based on very simplistic “perfect” computers) But they are beyond my comprehension so I cannot explain them to you But they are beyond my comprehension so I cannot explain them to you And they are probably beyond your comprehension as well And they are probably beyond your comprehension as well And you are probably thinking when will this presentation end And you are probably thinking when will this presentation end

22. The End

23. References Peercy, Paul S. “The Drive to Miniaturization.” Nature. Aug 2000: 1023- 1026. Peercy, Paul S. “The Drive to Miniaturization.” Nature. Aug 2000: 1023- 1026. Pescovitz, David. “Wired for Speed.” Scientific American. May 2000: 41-42. Pescovitz, David. “Wired for Speed.” Scientific American. May 2000: 41-42. Mullins, Justin. “Integrated Circuits.” New Scientist. Dec 2000: insert 1-4. Mullins, Justin. “Integrated Circuits.” New Scientist. Dec 2000: insert 1-4. Ito, Takashi and Okazaki, Shinji. “Pushing the Limits of Lithography.” Nature. Aug 2000: 1027-1031. Ito, Takashi and Okazaki, Shinji. “Pushing the Limits of Lithography.” Nature. Aug 2000: 1027-1031.