Ion-induced, UV-induced, and electron-induced sequential chemical vapor deposition (CVD) processes are disclosed where an ion flux, a flux of ultra-violet radiation, or an electron flux, respectively, is used to induce the chemical reaction in the process. The process for depositing a thin film on a substrate includes introducing a flow of a first reactant gas in vapor phase into a process chamber where the gas forms an adsorbed saturated layer on the substrate and exposing the substrate to a flux of ions, a flux of ultra-violet radiation, or a flux of electrons for inducing a chemical reaction of the adsorbed layer of the first reactant gas to form the thin film. A second reactant gas can be used to form a compound thin film. The ion-induced, UV-induced, and electron-induced sequential CVD process of the present invention can be repeated to form a thin film of the desired thickness.