Infra-red transparent optical components

Abstract

Abstract A method of coating a substrate in a glow discharge chamber uses a source of hydrocarbon and another element. Butane and germane are used to deposit a coating of Ge x C 1-x where 0<x<1 onto a germanium substrate. The substrate temperature is maintained above 400° C., typically 530° C., during growth to prevent inclusion of H 2 in the coating. The presence of Ge in the coating allows thick, stain-free, layers to be grown. Alternatively, butane and silane may be used to deposit Si x C 1-x . Varying the proportions of the hydrocarbon and germane or silane allows a variation in the value of x. A method of growing a combined layer of at least a first and a second material in glow discharge chamber. A target cathode formed on the first material, e.g., Si, Ge, W is arranged in the chamber and spaced from a substrate to be coated. Argon gas and a gas of the second material, e.g., a hydrocarbon, are admitted into the chamber and a glow discharge established. Hydrocarbon ions from the glow discharge plasma strike and deposit on the cathode target. Argon ions sputter off atoms of both C and bulk target material, e.g., Si, Ge, or W, which deposit onto the substrate and gradually build up a combined layer of, e.g., Si x C 1-x , Ge x C 1-x , W x C 1-x wherein 0<x<1. Optical lens components, infra-red transparent, made from these processes are also disclosed.

Inventors

• 👤 Geoffrey W. Green
• 👤 Alan H. Lettington

Bibliographic Details