The authors found high etch rates (similar to 0.4 mu m min(-1)) for GaAs in a capacitively coupled plasma (CCP) system using BCl3/N-2 discharges even at an operating pressure of 150 mTorr, which allows the use of simple mechanical pumps. There was a catalytic effect of the N-2 gas in BCl3/N-2 plasmas during the CCP etching. Optical emission spectroscopy data show an increased neutral atomic chlorine, and positive ion density is the cause of the increased GaAs etch rate with N-2 addition to the BCl3. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3079665]