A method of depositing a thin film on a substrate in a deposition system is described. The method includes disposing a gas heating device comprising a plurality of heating element zones in a deposition system, and independently controlling a temperature of each of the plurality of heating element zones, wherein each of the plurality of heating element zones having one or more resistive heating elements. Additionally, the method includes providing a substrate on a substrate holder in the deposition system, wherein the substrate holder has one or more temperature control zones. The method further includes providing a film forming composition to the gas heating device coupled to the deposition system, pyrolyzing one or more constituents of the film forming composition using the gas heating device, and introducing the film forming composition to the substrate in the deposition system to deposit a thin film on the substrate.