US 4,065,600 A · Metal oxide films

Abstract

In a method of depositing a transparent electrically conductive metal oxide coating by reactive sputtering onto the surface of a substrate, the substrate is supported, in spaced relationship with a cathode which is to be sputtered, in a vacuum chamber containing an atmosphere comprising an inert gas and a controlled oxygen concentration at a selected total pressure. The substrate is heated prior to sputtering to a selected elevated temperature, and reactive sputtering is caused by applying a selected negative potential relative to the substrate. The oxygen in the atmosphere is provided and maintained at a selected concentration, and the heating of said substrate is controlled during sputtering to maintain the substrate temperature substantially constant at the selected temperature during substrate heating caused by sputtering. The selected values of the oxygen concentration substrate temperature, vacuum chamber pressure, and cathode potential are so chosen that the deposited coating is haze-free, and its specific electrical resistivity lies at or close to the minimum of the curve which is obtained by plotting specific electrical resistivity against oxygen concentration while maintaining the substrate temperature, vacuum chamber pressure and cathode potential all constant at the selected values. Glass articles with stable, transparent and haze-free coatings having acceptable resistance are produced by the method.

Claims42

Dependent claims

A method of depositing a transparent electrically conductive metal oxide coating by reactive sputtering onto the surface of a substrate, wherein:

the substrate is supported, in spaced relationship with a cathode which is to be sputtered, in a vacuum chamber containing an atmosphere comprising an inert gas and a controlled oxygen concentration at a selected reduced total pressure, the substrate is heated prior to sputtering to a selected elevated temperature, and reactive sputtering is caused by applying a selected negative potential to the cathode relative to the substrate, the oxygen in the atmosphere being provided and maintained at a selected concentration, and the heating of said substrate being controlled during sputtering to maintain said substrate temperature substantially constant at said selected temperature during heating of said substrate caused by sputtering, the selected values of the oxygen concentration, substrate temperature, vacuum chamber pressure, and cathode potential being so chosen that the deposited coating is haze-free, and its specific electrical resistivity lies at or close to the minimum of the curve which is obtained by plotting specific electrical resistivity against oxygen concentration while maintaining the substrate temperature, vacuum chamber pressure and cathode potential all constant at said selected values.

A method of depositing a transparent electrically conductive metal oxide coating onto the surface of a glass substrate by reactive sputtering, the process comprising the following steps:

supporting the substrate in a chamber in spaced relationship with a cathode of an alloy which is to be sputtered,
evacuating the chamber,
heating the surface of the substrate to a selected temperature in the range of from 200.degree. to 350.degree. C before commencing sputtering,
providing an atmosphere in the chamber comprising an inert gas and a controlled oxygen concentration and maintaining the pressure of the atmosphere in the chamber at a selected value of from 10 to 100 microns Hg,
maintaining the oxygen in the space between the cathode and the substrate at a selected oxygen concentration within the range of 1 to 9% by volume,
causing deposition of a metal oxide film on the substrate by reactive sputtering by applying a negative potential to the cathode selected such that the potential difference between cathode and substrate is in the range of from -1kV to -5kV, and
controlling the heating of the surface of the substrate during sputtering to maintain the substrate temperature substantially constant at said selected temperature,
the selected values of the oxygen concentration, substrate temperature, vacuum chamber pressure, and cathode potential being so chosen that the deposited coating is haze-free, and its specific electrical resistivity lies at or close to the minimum of the curve which is obtained by plotting specific electrical resistivity against oxygen concentration while maintaining the substrate temperature, vacuum chamber pressure and cathode potential all constant at said selected values.

5 more elements

Dependencies are inferred from the claim text.

Metal oxide films

Life of this patent

Metal oxide films

Life of this patent

Abstract

Claims42