Most of it isn't strictly necessary. Like, he has sputtering equipment for making layers that can't be chemically deposited for example. The one where he makes a MOSFET on camera involves just spin coating with tape and some random motor, a little tube furnace to bake impurities in and chemical etching IIRC.

He uses commercially available blank wafers; you'd need a small arc furnace (or at least a blast furnace and patience when your product is mostly iron) to make silicon from sand and something resembling a meth lab to clean it (and then you'd grow and cut your wafer, but that could be done on a desk I'm sure).

It didn't look that hard in the transistor video, actually. His layers were in no way straight or pretty, all that matters is the topology and timing on the baking steps.