Method and apparatus for forming thin film oxide layers using reactive evaporation techniques
AssigneeOptical Coating Laboratory, Inc.
InventorHarold Gurev
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Abstract
Apparatus and method for forming high quality thin film oxide layers on a substrate by a reactive evaporation process utilizing an oxygen plasma activation source in the form of a cylindrical boule of insulating material surrounded by a radio frequency coil for generating a radio frequency electromagnetic field in the boule of sufficient magnitude to create a self-igniting oxygen plasma within the boule without evaporating material from the walls thereof.
Claims10
In a method of reactively depositing an oxide coating on a substrate in a vacuum deposition system which includes a vacuum chamber and an evaporation source disposed in said chamber, the steps of:
- disposing a plasma source in a position to communicate with the interior of said chamber and comprising a boule of preselected insulating material defining a substantially closed cavity and a coil arrangement disposed generally around said boule and adapted to be connected to a supply of radio frequency energy to create a radio frequency electromagnetic field within said cavity;
- supplying to said cavity a continuous flow of oxygen at a preselected flow rate;
- supplying radio frequency energy to said coil arrangement at a power level preselected to be below the power level required to evaporate material from the walls of said boule but sufficient to create a self-igniting oxygen plasma within said cavity;
- disposing said substrate in said vacuum chamber in the path of activated oxygen molecules emanating from said plasma source;
- and
- evaporating a selected material onto a surface of said substrate from said evaporation source.
In apparatus for reactively depositing an oxide coating on a substrate, in combination:
- a vacuum chamber;
- means for evacuating said chamber;
- means for positioning a substrate of selected material in said chamber;
- an evaporation source disposed in said chamber for depositing a preselected material onto said substrate;
- a plasma activation source mounted to said chamber and comprising a boule of preselected insulating material defining a substantially closed cavity communicating with the interior of said vacuum chamber, a conductive coil arrangement disposed generally around said boule, and piping means for communicating a supply of oxygen to said cavity;
- and means for supplying a radio frequency signal to said coil means to produce a radio frequency electromagnetic field within said cavity having a preselected magnitude of energy sufficient to create a self-igniting oxygen plasma within said cavity but insufficient to evaporate material from the walls of said boule.
Dependencies are inferred from the claim text.