Another thought
I had a situation where I had to control a very precise Boron/shallow diffusion, I used an O2 descum tool to give me about 200A on oxide to slow things down.
If you have access to an O2 plasma cleaner, oxide thicknesses can be very well controlled using this method.
Just a...
Greetings
I realize I may be a little late on this (just joined/first post) but I'll assume you can't answer process questions so I'll just think out loud.
if we are talking about a tube operation (diffusion tube)then the item to be oxidized should be loaded in to your hot zone in an N2...
