Patent ID: 6260510
Filing Date: 2001-07-17
Classification: C03B,C23C,H01J,Y02P

Abstract:
An apparatus for performing Plasma Chemical Vapor Deposition, whereby one or more layers of silica can be deposited on an elongated vitreous substrate, the apparatus comprising an elongated microwave guide which emerges into a resonant cavity which is substantially cylindrically symmetric about a cylindrical axis, along which axis the substrate can be positioned, the cavity being substantially annular in form, with an inner cylindrical wall and an outer cylindrical wall, the inner cylindrical wall comprising a slit which extends in a full circle around the cylindrical axis, and the guide having a longitudinal axis which is substantially perpendicular to the cylindrical axis and which does not intercept the slit, wherein the width W of the slit and the length L of the resonant cavity, both measured in a direction parallel to the cylindrical axis, satisfy the relationship: W.ltoreq.L/10.