**Silicon, Circuits, and the Digital Revolution**

**Concentration of Doping - Semiconductors
into Metals **

- Review effects of doping on resistivity of semiconductor

-- figure from Ashcroft and Mermin "Solid State Physics" showing antimony-doped germaniumDonor Concentration Resistivity (micropercent) (ohm-cm) 5 10 ^{9}50 10 ^{5}150 10 300 0.1 - the first factor of ten increase in doping leads to a factor of ten-thousand increase in conductivity!
*For comparison, this is like a return of $2 on a $1 investment, shooting up to a $20,000 return on increasing to a $10 investment...*- a factor of 60 variation in doping level results in
**ten**orders of magnitude variation in resistivity. - converts germanium effectively into a metal!

Comments, suggestions, or requests to ghw@udel.edu.
"http://www.physics.udel.edu/~watson/scen103/colloq2000/doping-concentration.html" Last updated April 20, 2000. © George Watson, Univ. of Delaware, 2000. |