Published online by Cambridge University Press: 21 February 2011
Corrosion of the Si(100) surface by concentrated NH4F solutions was studied using high spatial resolution secondary electron imaging in an ultra-high vacuum scanning transmission electron microscope. Various corrosion mechanisms were investigated by varying the ex-situ chemical treatment of the samples. Entirely different surface morphologies were obtained for surfaces that were kept in solution for short times (-minutes) vs. long times (∼24 hours) and surfaces which were rinsed in DI H2O vs. those which weren't. These measurements confirm that corrosion continues after the samples are removed from the solution and seems to be correlated with the formation of the Si hexafluorometallate salt. This salt is extremely electron beam sensitive and desorbs in UHV at temperatures below 250°C.