So he "only" did metal deposition to make the interconnects? I haven't read the story, but I was thinking that there's no way you would handle some of the toxic chemicals used for doping.
Good dopant choices would be phosphorus oxychloride and oxidized boron nitride wafers.
As I recollect, he started with silicon wafers with an epitaxy layer. He then did the usual oxidations, diffusions, and metallization, along with all the photolithographic steps. No small feat!