We describe the design, construction, and calibration of Knudsen cell evaporators for the chemical vapor deposition of organic films. The evaporators can easily be constructed using equipment and materials available in most labs. We employed them to codeposit monomers for polyimide formation. The vapor deposition process of polyimide and other polymeric materials can be controlled to form ultrathin films suitable for the investigation of the interaction between the overlayer and the substrate. We describe a deposition system used to produce polyimide films from 2 nm to more than 1000 nm thick on 1- to 2-cm-diam substrates at growth rates from similar to 1 nm/min to more than 10 nm/min. (C) 1995 American Institute of Physics.