1. Silicon, Circuits, and the Digital Revolution George Watson Department of Physics and Astronomy University of Delaware ghw@udel.edu June 1, 1999 ALLSTEL

2. Silicon, Circuits, and the Digital Revolution http://www.physics.udel.edu/~watson/scen103/ http://www.physics.udel.edu/~watson/scen103/ The Way it Was: Technology on Campus 25 years ago Slide Show

3. Silicon, Circuits, and the Digital Revolution Everything is made of something! Atoms are comprised of nuclei and electrons. Mass is nuclear. Size is electronic.

4. Electron Energy Levels in Hydrogen

5. The Visible Spectrum Photon “color”WavelengthEnergy (nm)(eV) blue4302.9 yellow5302.3 red6501.9

6. Electron Energy Levels

7. Electronic Band Structure in Solids

8. Metals, Insulators, and Semiconductors

9. Column 4: Silicon among the elements

10. Band Gaps of Column 4 Elements ElementBand Gap (eV) Carbon (diamond)5.5 Silicon1.1 Germanium0.7

11. The Visible Spectrum Photon “color”WavelengthEnergy (nm)(eV) blue4302.9 yellow5302.3 red6501.9

12. Metals, Insulators, and Semiconductors

13. Concept Check: Band Gaps You are admiring the color of a gemstone by looking through it to see a nearby lamp. Your physicist friend states that the band gap of that particular stone is about 2.4 eV. Does the stone appear to be: a. red b. blue c. black

14. Band Gaps of Several Elements ElementBand Gap (eV) Carbon (diamond)5.5 Silicon1.1 Germanium0.7 Selenium1.8

15. Silicon, Circuits, and the Digital Revolution Principle of photoconductivity applied to photocopying: xerography (dry writing) Slide Show

16. Essentials of Xerography

17. Pure silicon - 4 valence electrons From sand?

18. Column 5: one more valence electron

19. Silicon doped with arsenic n-type silicon

20. Column 3: one fewer valence electron

21. Silicon doped with gallium p-type silicon

22. Effect of doping on band structure

23. Transistors are structured from n-type and p-type silicon.

24. Concept Check: doped silicon You physicist friend hands you a wafer of germanium and tells you it is doped with phosphorus. Is the semiconductor wafer: a. n-type b. p-type

25. Silicon, Circuits, and the Digital Revolution Building Transistors on Integrated Circuits: lithography (stone writing) Slide Show

26. MOSFET inverter

27. CMOS inverter

28. CMOS fabrication

29. CMOS NAND gate 4 transistors

30. Adder circuit 38 transistors!

31. Moore’s Law for Intel Microprocessors

32. Penetration rates of major consumer products in U.S. households