Plasmas and Polymers, Vol. 6, Nos. 1/2, June 2001 ( c  2001) Ultrathin Silicon-Compound Barrier Coatings for Polymeric Packaging Materials: An Industrial Perspective G. Czeremuszkin, 1 M. Latr` eche, 1 M. R. Wertheimer, 2,3 and A. S. da Silva Sobrinho 2,4 Received January 8, 2001; accepted May 29, 2001 Growing demands for increased shelf-life of food products and chemical inertia of the contact surfaces have stimulated development of polymers with improved high-barrier properties. Our objectives in this article are (1) to describe experimental results on Plasma-enhanced chemical vapor deposition (PECVD) and its importance to produce thin layers of inorganic glassy barrier materials for food, pharmaceutical, and organic display applications; (2) despite the thereby greatly enhanced quality of film or rigid packaging material, some residual coating defects result in less-than-perfect gas, mois- ture and aroma barriers: an innovative technique based on reactive ion etching (RIE) in oxygen plasma is also presented, along with a staining method, which render even sub-μm coating defects visible. Data are shown for oxygen transmission rate on virgin and defective coatings, and the industrial context and applications are presented. KEY WORDS: PECVD; silicon dioxide; gas barrier; plastics; packaging. 1. INTRODUCTION The permeation of gases (e.g., O 2 , CO 2 ) and vapors (e.g., H 2 O, aromas and flavors) through polymers represents an important problem in their use as packag- ing materials. It is well known that the permeation through a polymeric membrane is a solubility/diffusion-controlled process, and extensive determinations of the mass transport rates have been made. (1) In order to reduce the rate of permeation of gases and vapors through polymers, several barrier options have been proposed 1 Nova-Plasma Inc., Montr´ eal, QC, Canada. 2 Department of Engineering Physics and Materials Engineering, Ecole Polytechnique, Montreal, QC H3C 3A7, Canada. 3 To whom correspondence should be addressed. E-mail: mwertheimer@courriel.polymtl.ca 4 Current address: General Electric Corporate Research and Development, Schenectady, New York 12301. 107 1084-0184/01/0600-0107$19.50/0 C  2001 Plenum Publishing Corporation