Film synthesis techniques used in the laboratory are based in physical or chemical vapor deposition of thin films ('physical vapour deposition' or PVD and 'chemical vapour deposition' or CVD, respectively).
In both cases, the techniques are based in the formation of vapor of the material to be deposited, so that the vapor is condensed on the substrate surface as a thin film. Usually the process must be performed in vacuum or in controlled atmosphere, to avoid interaction between vapor and air.
In physical techniques (PVD) we part from a solid material converted to vapor through heating (evaporation) or energetic ion bombardment. The material in form of vapor finally condeses on the substrate surface as a thin film.
In chemical techniques (CVD) we part directly from gases (sometimes vapor originating from a liquid phase) which react and give place to a new product that condenses as a thin film on the substrate.
Other film synthesis techniques include high temperature thermal oxidation and anodic oxidation.
An essential difference between PVD and CVD techniques is that in the first ones the material to be deposited already exists (in solid form), while in the second ones the material does not exist previously: it is synthesized in vapor phase