Can silicon based computers create A.I. per definition of what
What definition? There are many definitions of intelligence, and no universally accepted one that I'm aware of.
Or does silicon based computers only create human mimic?
It's not clear to me what you're asking. If humans are intelligent and we mimic humans closely enough, then it's probably fair to call the-thing-we-built "intelligent".
If silicon based computers only create human mimic, are human mimic intelligence per definition?
I'm still not clear what you're asking, but I think I would answer "yes" if I'm parsing this correctly.
If not, how can we create A.I. per definition of what intelligence is?
Again, we don't really have a definition of what intelligence is. But so what? Who says AI has to have anything to do with human intelligence at all? As the old saying goes "man did not achieve flight by building a mechanical bird". Likewise, there's no specific reason to think that the only path to artificial intelligence is to replicate the human brain in silicon.