[sdiy] Having a hard time finding the chips you want - roll your own!

[ElmacacoX at aol.com]

so I guess environmentally friendly sdiy is pretty much out of the question? 
; )

"Grow a layer of silox (silicon dioxide) on top of this
Apply photoresist, expose the isolation mask, develop, and etch the exposed
silox away (just like a PC board!), remove photoresist.
Stick it in a diffusion oven and blow boron gas at it at about 1100 degC to
diffuse p-type material all the way through the epi layer to the p-type
wafer. This defines tubs of n-type material.
Grow another silox layer, apply photoresist, and expose the base layer
(will become base of npn transistors), etch, and strip photoresist.
Another p-type diffusion step to define the bases of npn transistors, and
resistors - islands of p-type material inside of the n-type tubs.
Another silox layer and mask exposure to define the emitter areas.
Another diffusion step, this time with n-type gas (phosphine)
Another silox layer and exposure and etch to define contact openings down
to the components.
Sputter aluminum over the whole thing.
Photoresist and exposure for the metal mask, etch.
Another silox layer, then a mask to define the pad openings (where the
little wires will bond to), etc."