Cryogenic control of chemistry in plasma deposited organic films
We have investigated reducing the substrate temperature during plasma deposition as a means for controlling film chemistry. We hypothesize that because the glow discharge is a weakly ionized plasma, by reducing the surface temperature during film growth, the concentration of unfragmented precursor (the vapor being ionized) in the region of film growth can be increased by adsorption or condensation. Experimentation has shown that cryogenic substrate temperature during plasma deposition can be used to control film chemistries for several precursor types. The degree to which control can be maintained depends on the type of precursor used, the film temperature and the power level of the plasma (i.e., degree of fragmentation/ionization). There may be more than one mechanism leading to predictable film chemistry.
Lopez, GP; Ratner, BD
Polymeric Materials Science and Engineering, Proceedings of the ACS Division of Polymeric Materials Science and Engineering