Characteristics of Polytetrafluoroethylene Thin Films Prepared by Ionization-Assisted Deposition

Hiroaki USUI  Hiroshi KOSHIKAWA  Kuniaki TANAKA  

IEICE TRANSACTIONS on Electronics   Vol.E81-C   No.7   pp.1083-1089
Publication Date: 1998/07/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Organic Materials for Optics and Electronics)
ionization-assisted deposition,  ion beam,  polytetrafluoroethylene,  PTFE,  electrical insulation,  Cu decoration,  

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Thin films of PTFE (mean molecular weight of source material 8500) were deposited by ionization-assisted deposition (IAD) method at different ion acceleration voltages Va on substrates kept at room temperature. The molecular chains in the film were found to be oriented in parallel with the substrate, and the film has preferential crystal orientation to (100) plane. Although the ion acceleration did not give significant influence on the film orientation and chemical structure, IAD was effective to improve the surface smoothness. The Cu decoration test revealed that the pinhole density in the film is reduced and the insulating capability is improved by depositing the film at Va = 500 V. The result of dielectric loss measurement for Al/PTFE/Al capacitors was in consistency. However, excessive ion acceleration deteriorated the insulating property, probably due to the dielectric breakdown that occurred in the course of deposition.