STP1141

    Fabrication and Characterisation of Microwave Plasma Assisted Chemical Vapour Deposited Dielectric Coatings

    Published: Jan 1991


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    Abstract

    A microwave plasma assisted chemical vapour deposition (MPACVD) process has been used to deposit modulated refractive index profile dielectric films to meet specific reflectance/transmittance coating characteristics.

    The MPACVD process has been proven to allow the deposition of dielectric thin films of excellent optical quality which have lower scatter and less strain than most conventional coatings. An important feature of the process is that both the deposition rate and the composition of the film can be adjusted under computer control during the deposition process. This degree of control allows the deposition of both graded and even more complicated refractive index profiles. The technique therefore allows the successful realisation of highly sophisticated coating designs (e.g. Fourier).

    The process has been used to fabricate a range of dielectric designs, including narrow band high reflectivity coatings with minimal sidebands, using silicon oxynitride on fused silica substrates. This paper discusses aspects of the MPACVD process, including deposition rate, control, uniformity and deposition quality, the Fourier design program and the characteristics of a range of coating trials. The measurements made have included optical, laser and limited environmental testing.


    Author Information:

    Wood, RM
    GEC-Marconi Ltd, Hirst Research Centre, Wembley, Middlesex

    Greenham, AC
    GEC-Marconi Ltd, Hirst Research Centre, Wembley, Middlesex

    Nichols, BA
    GEC-Marconi Ltd, Hirst Research Centre, Wembley, Middlesex

    Nourshargh, N
    GEC-Marconi Ltd, Hirst Research Centre, Wembley, Middlesex

    Lewis, KL
    GEC-Marconi Ltd, Hirst Research Centre, Wembley, Middlesex


    Paper ID: STP23639S

    Committee/Subcommittee: F01.19

    DOI: 10.1520/STP23639S


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