Doping is when we add impurities to the extremely pure silicon. This changes the electrochemical properties of the silicon. Silicon is in group 4 of the periodic table. Like Carbon it makes nice solid bonds in 4 directions. By adding elements from the 3rd or 5th columns we can add extra electrons or extra positive charges (holes where there are no electrons).

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The elements we typically use are Boron for p-type (positive holes) doping and Phosphoros or Arsenic for n-type (extra electrons) doping.

The Arsenic is the poison in this fun tweet:

computers think using etchings in poisoned sand and measure time using vibrating crystals so if you were looking for magic you found it

— Computer Facts (@computerfact) April 20, 2016

For more information check this article from technocrazed

Course feedback

For a very long time I’ve been fascinated by ASICs and have been close to them in my professional life as well, but not really as much into the detail as I would want. It’s been a fascination since grad school at least, so I've been interested in seeing more open source alternatives crop up, and now with the skywater PDK and OpenLane it seemed like the right time. It’s still a bit hard to get the motivation to get started, it feels like a bit of a hurdle so when I saw this course I just jumped right on it. It felt like a perfect way to get started.

Klas Nordmark