How do foundries actually dope silicon when chipmaking? 409 viewsOctober 7, 2019 Question34.21K October 7, 2019 1 Answer So i get that transistors are basically 2 diodes sandwiched together and photo-etched onto silicon but how do you make those negative and positively doped zones that a transistor needs when we’re talking about nanometers in terms of dimensions? In: Engineering incruente commented October 7, 2019 The entire ingot can be doped by including certain impurities when making it (or by exposing it to a powerful neutron flux from a nuclear reactor). But the tiny individual doping operations are done photographically. A compound is placed on the wafer, and a mask is used to expose certain areas of it to light to harden it. The parts that did not get hardened can be washed away with chemicals, leaving only specific areas of silicon exposed to be doped. Then, the hardened areas are removed with other chemicals. Rinse and repeat. 0 Answers ActiveVotedNewestOldest Register or Login Other Questions You Might Be Interested In: Why is alcohol measured in ABV instead of the size of an actual measurement, like they do with marij...eli5: what actually makes a deep voice attractive?eli5: Why is lemonade more refreshing than water sometimes?Why is it that after eating spicy food, eating hot (as in temperature) food is so much more painful?why do humans need to eat many different kind of foods to get their vitamins etc but large animals l...Why do diamonds sparkle but other carbon-based materials do not?