Plasma-enhanced chemical vapor deposition (PECVD) has been used to deposit transparent, conducting tin oxide from mixtures of SnCl4 and O-2. The chemistry of this system was investigated using statistically designed experiments, in-situ optical emission spectroscopy (OES), and ex-situ measurements of film properties. Experiments revealed that plasma power and substrate temperature were strongly coupled. The combination of higher power and temperature was synergetic, yielding improvements in both deposition rate and electrical conductivity at low SnCl4 flow rates. A number of unique OES signals were identified in this system. Emission signals attributed to tin-containing intermediates and atomic Cl were correlated with electrical performance and growth rate, respectively. Based on these measurements a mechanism is proposed to explain the non-linear growth behavior observed in this system.