OK,

As i know RCA1 is H2O:H2O2:NH3;6:1:1 at 60 celcius

so, to my knowledge nh3 is a solvent for too many metals except gold and chromium.

on my ewperiment i only seen the HF is damaging the surface of silicon wafer.

my idea is nothing happens to inside of the silicon wafer during rca proccess. H2O2 and NH3 mix gives me the idea of this proccess is sticky metallical contaminat are being removed. on the other hand 60 celcius is not high Si wafer.