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Re:The science of ultra pure silicon
by tabletopneedle on Saturday August 11, 2018 @07:51AM
(#17739327)
For example, cleanroom has classification that implies some amount of dust particles/impurities in the air. The technicians don't talk about the number of dust particles allowed, they just consider class 5 suitable for some applications whereas others might need class 4.
Class 4 cleanroom makes sense, as does "Ultra pure" as long as industry sees it as a standard.
Another example: UHD makes as little sense as FHD in terms of display resolution. I mean, Full must mean it's at maximum possible amount of high definition? Well we just know it stands for 1920x1080, and we know UHD or 4K is larger.
Only to you, if you observe it out of the context. The practice is completely different, and the OP article wasn't incorrect.
http://www.thequartzcorp.com/en/applications/silicon-metal.h...
"For silicon metal to be used in solar and semiconductor applications it must be extremely pure. For solar applications, the metal must be 99.9999% Si, while semiconductor applications require 99.999999999% purity. No quartz product can be purified above 99.999% SiO2, which means silicon metal must go through successive purification processes before it can be used."
As you see, the common use in the industry of "pure" is somewhat as "went through the process of the purification," therefore if it is purified more than what is commonly referred to as "pure" then it's "extremely pure" or can even be called "ultra pure" (edit: note, in the sense of "purer than what is typically offered as pure" and not in the sense of "more than what anyway doesn't exist").
In practice, anything "completely" purified, so that "not even single atom of the impurity remains" simply doesn't exist. There's no absolute, only different achieved levels of what is commonly called "pure": See e.g. "Purest silicon sphere ever created":
https://www.chemistryworld.com/news/purest-silicon-sphere-ev...
The common usage, that you object to, reflects the reality.