The mechanism of formation and some properties of thin fluorocarbon films deposited onto silicon plates by electron-beam polymerization of hexafluoropropylene from the vapor phase

Abstract

The results of studying thin fluorocarbon films deposited onto single-crystal silicon plates through electron beam polymerization of hexafluoropropylene from the vapor phase are presented. The films are deposited under the action of an electron beam with an energy of 40 keV at a monomer vapor pressure of 5- 20 hPa. It is shown that plastic solid films consisting of a low-molecular-mass polymer with low thermal stability are formed at a beam current density on the order of 20 μA/cm2, while at current densities on the order of 150 μA/cm2, rigid brittle films of three-dimensional crossl inked polymer are formed with a thermal stability of about 350°C. It is assumed that the films are formed via chain polymerization, which at high current densities, is accompanied by polyrecombination processes leading to efficient chain crosslinking. It is found that polymer clusters are ordered in the course of film formation.