Based on analysis by in situ Auger electron spectroscopy, partially oxidized Cr films, 3-10 nm thick, were etched by the combination of 2 keV electrons and Cl-2(g). The Cl-2 gas pressure in the area irradiated by the e beam is critical and must be in the mTorr regime. For the flux (8 mA cm(-2)) of electrons used, the etching rate saturated for estimated local Cl-2 pressures above 2 mTorr. The effects on etching of small amounts of Si are described. (C) 2005 American Vacuum Society.