They are not really that toxic. You do have to have a chemistry background and use a fume hood and a process sink with acid neutralization capability, like you find in many chem labs.
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!
