Method and apparatus for forming thin film oxide layers using reactive evaporation techniques

Claim 1

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.

Claim 5

The method of any of claims 2 or 3, wherein said substrate is glass, said substrate is heated to an initial temperature of around 100 degrees centigrade prior to said evaporation step, and said evaporation step is carried out for a period of time sufficient to deposit a tin-doped indium oxide film to a thickness of about 300 Angstroms.