We made transistors in a freshman class at Caltech in 1986. I seem to recall that there was hydrofluoric acid and a furnace involved. HF is nasty stuff.
A few years ago, I scanned some of the lab and TA notes from that class (~1991 vintage) for a guy that wanted to DIY some semiconductors in his garage. Neat project; I should try to locate him and see if he made any progress.
It really does emphasise how most inventions are collective efforts building on many incremental steps and seldom moments of sheer eureka type brilliance.