The temporal profiles of metastable F(4P3/2) and Ar(1s5) and emitting F(4D05/2) and Ar(2p2) in a sharp‐edged, pulsed CF4/O2/Ar (87.5/10.4/2.1) discharge are discussed. All four states are so short lived that there is no net accumulation during the discharge pulse and the profiles merely reflect the formation rate. For Ar, electron impact on the ground state leads to both excited states. Their similar profiles mirror the electron excitation function. For excited F, two channels are open: electron impact on CF4, and electron impact on ground‐state F which accumulates during the discharge pulse. The fact that metastable F is rapidly quenched in the gas phase indicates that it is not a major etchant of silicon or silicon nitride as was recently suggested in the literature.