Abstract: A process and associated system for vapor deposition of a thin film layer on a photovoltaic (PV) module substrate is includes establishing a vacuum chamber and introducing the substrates individually into the vacuum chamber. The substrates are pre-heated as they are conveyed through the vacuum chamber, and are then conveyed in serial arrangement through a vapor deposition apparatus in the vacuum chamber wherein a thin film of a sublimed source material is deposited onto an upper surface of the substrates. The substrates are conveyed through the vapor deposition apparatus at a controlled constant linear speed such that leading and trailing sections of the substrate in a conveyance direction are exposed to the same vapor deposition conditions within the vapor deposition apparatus. The vapor deposition apparatus may be supplied with source material in a manner so as not to interrupt the vapor deposition process or non-stop conveyance of the substrates through the vapor deposition apparatus.