Silicon is purified to around 99.9999999%! Then it is sliced into very thin round sheets called wafers.
The type used in the Skywater 130nm process is doped to become p-type.
I found these great videos about the birth of the Japanese semiconductor industry. Jump to about 12 minutes in to see
how they pull the silicon ingot out of the molten material.
After the wafers are ready, they can be patterned using the photolithographic process, using a series of masks
It was a great fun way to introduce people to Verilog and basic digital design in general. You don't have to have done tons of FPGA stuff or be an expert at Verilog at all. If you’re interested in hardware in general I'd say it's accessible.