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.

Here’s a great video about how silicon wafers are made.

And these great videos are 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.

Course feedback

The part I enjoyed the most was going back to the Verilog and seeing test benches pass. In particular the waveform viewer. At the latter parts of course you're simulating the entire Caravel system on chip with a RISCV core. Being able to drill down into everything inside that core, I can log the program counter, I can log all the address and data buses and you can just see in exquisite detail what the system is doing, and it's doing that because I programmed it. Being able to drill down into that detail was really fascinating.

Jonathan Pallant (digital course)