Vapor-deposited polymeric-organic composite films

Over the past few years, polymeric films have played an important role in advanced IC technologies and optoelectronics. In depositing these polymeric films with tailorable and desired properties, vapor deposition techniques have potential advantages over spin-on techniques. This thesis explores the vapor deposition of polymeric-organic composite films, and investigates the resulted Nm's composition, structure and electro-optic (EO) effect. The source materials chosen are the newly commercialized polymer, Teflon AF;We developed a novel two-step deposition process to fabricate smooth and uniform Teflon AF films using a physical vapor deposition technique. These films are found to be chemically equivalent to the spin-on films and source material. The films are always amorphous, but their morphology depends greatly on the deposition conditions.;We successfully co-deposited Teflon AF-DANS polymeric-organic composite films with large EO effects, which, to our knowledge, is the first to be reported for a vapor deposited composite EO film. A mathematical procedure to determine the composition of the composite films using x-ray photoelectron spectroscopy (XPS) was developed, and the compositions, structures, and electro-optic effects of the composite films were investigated. We find that Teflon AF-DANS composite films remain amorphous and there is no interaction between Teflon AF and DANS components when the DANS density is below 10%. The films behave as a pure guest-host system with the DANS molecules dispersed in a Teflon AF matrix, the increase of electro-optic effects following a DANS composition increase. At DANS concentrations of 10%, the EO coefficient reaches its maximum value of about 2.4 pm/V, which is close to that predicted by theory. The decrease and disappearance of EO effects in the films with high DANS density are believed to be caused by an anti-pair effect and phase separation since the DANS anti-pairs and DANS crystallites have no contribution to EO effect. The anti-pair effect can begin to manifest at concentration of 10% DANS due to the dipole-dipole interaction among highly polar DANS molecules, and phase separation is found in films containing more than 25% DANS.