eli5 How are transistors made so crazy small?
In: 7
Silicon + lithography.
Silicon’s important because it can be doped to change its properties, so we can create semi-conductors that change conductivity based on a control signal.
Lithography basically means using light and chemicals to print different layers of doping/metal traces/etc onto the silicon.
So we start with a thin disk of silicon and cover it in a thin photo resist which forms a protective coating. Then we project a stencil onto the photoresist as light, which damages it where it’s exposed to the light allowing a acid bath to wash off the resist in those places (or in some cases they use a resist that hardens under light and the unlit areas wash off).
Now you can use another chemical to dope the exposed silicon, cut grooves, deposit metals, etc.
Because the light pattern can be extremely exact, you can create incredibly tiny details. Allowing for insanely small transistors to be formed.
Latest Answers