Infrared diode laser absorption spectroscopy has been used to detect the A-X electronic spectrum of diatomic SiN in a SiCl4/N-2 plasma. The. intensity of the SiN transitions with respect to the ratio of SiCl4:N-2 flow rate was investigated. A correlation between intense signals of SiN and the optimal growth conditions for a-SiN films reported in literature was found. This observation lends support to the importance of diatomic SiN as a film precursor. The electronic emission spectra of silicon-containing transient species were also recorded in the plasma. A brief discussion of the plasma reaction pathways of SiN is presented. (C) 2002 Elsevier Science B.V. All rights reserved.