We report oninsitudetection of diatomic products of plasma sputtering and reactive ion etching using the technique of laser‐induced fluorescence. The diatomic molecules SiN, SiO, and SiF are observed in the gas phase when a silicon surface is subjected to ion bombardment in plasmas containing N2, O2, and CF4, respectively. Information about the production mechanisms is obtained from the measured product concentrations under varying plasma conditions.