Growing the MOS gate oxide without extreme cleanness has no chance of succeeding.
The difficulty of this process has caused a delay of many decades between the time when the MOS transistor was first imagined (in 1928 by Julius Edgar Lilienfeld, then also in 1935 by Oskar Heil) and the time when working MOS transistors were made for the first time, around 1960.
That's why early fabs had very unusual placement requirements: not close to chicken farms, agriculture, water, or sewage treatment plants.
Intel famously got seasonal yield losses which they traced to agricultural activities, and seasonal chicken coup cleaning.
Older, and cheaper fabs still rely on natural atmosphere, and other, less sure tricks to keep halogens out.
Be careful about purifying alcohol. Some backward countries have religiously-based legal prohibitions on this. My own backward country tightly controls acetone as a "precursor" to "stupefacients".
Nice thing about silane is that you don't have to worry about accidentally breathing it. There's a cheap and simple process for manufacturing it on demand from magnesium silicide, so you don't have to store it either.
I wonder if it would be possible to automate the entire process with robotics and reduce the effective "clean" space even further.
There was this post a while back about a company that used thin cassettes to keep the wafers clean when moving between process steps.
The good news here is that 2 of those 3 issues are pretty easily solvable. With some work, and a ton of HEPA air purifier machines, you could probably turn an area the size of a small shed or 1 car garage into a class 10000 cleanrom pretty easily. It would be simplest if this area were embedded in a larger area, like a 2 car garage, but, you could probably squeeze it into just a plain old 1 car garage.
Chemicals, you can buy online from scientific supply houses. Some, like acetone, you can buy from less specialized sources in high purity. Water and alcohol, you can either buy at high purity pretty easily, or buy lower grade stuff and purify it.
Of course, at the point where you're going for higher purity stuff like this, you might want to switch from acetone as a solvent to DMSO. DMSO itself is safe to handle and doesn't evaporate like acetone will.
> Silane
Yeah, nasty stuff. Toxic as hell, ignites spontaneously when exposed to air. I used to work near a rather large storage tank that contained the stuff. Needless to say, I am glad there never was an accident. :-) Very wise to avoid this stuff.
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https://www.americancleanrooms.com/class-10000-clean-room/
https://en.wikipedia.org/wiki/Dimethyl_sulfoxide
https://en.wikipedia.org/wiki/Silane