Patent GB-853852-A (GB)
Title: Improvements in or relating to methods of manufacturing electrically conductive films
IPC: C23C16/40
Filed: 1957-02-11
Abstract: Electrically conducting films are produced by mixing the halides of at least two elements, at least 90% of the mixture being a halide of tin, silicon or titanium, the remainder being the halides of at least one of hafnium, bismuth, niobium, tantalum, tungsten, nickel, copper, zinc and vanadium; evaporating such mixture and carrying the halide vapours in a stream of a carrier gas; contacting such gas stream with a dielectric base heated to a temperature high enough to decompose the halides; reacting the freed elements with a reactive gas comprising oxygen, ammonia or a mixture thereof to form oxides and/or nitrides of the elements as a deposit on the base, and removing excess vapour from the vicinity of the base.  The reactive gas may be introduced into the gas stream, or may comprise the stream: or the stream may be an inert gas such as hydrogen or nitrogen so that the freed elements are deposited as such on the base, which is then further heated in an atmosphere of the reactive gas: in the former case first oxygen, then ammonia may be introduced so that the oxide formed first is at least partially converted into nitride.  The base plate may be of high melting point glass; in order to coat only a part thereof with the conducting film, either the base is first painted with a masking composition where the film is not wanted, or the entire base is coated and unwanted film then removed by chemical action of zinc and hydrochloric acid.  An annular track for a sliding-contact potentiometer may be so produced.ALSO:Electrically conducting films are produced by mixing the halides of at least two elements, at least 90% of the mixture being a halide of tin, silicon or titanium, the remainder being the halides of at least one of hafnium, bismuth, niobium, tantalum, tungsten, nickel, copper, zinc and vanadium; evaporating such mixture and carrying the halide vapours in a stream of a carrier gas; contacting such gas stream with a dielectric base heated to a temperature high enough to decompose the halides; reacting the freed elements with a reactive gas comprising oxygen, ammonia or a mixture thereof to form oxides and/or nitrides of the elements as a deposit on the base, and removing excess vapour from the vicinity of the base.  The reactive gas may be introduced into the gas stream, or may comprise the stream: or the stream may be an inert gas such as hydrogen or nitrogen so that the freed elements are deposited as such on the base, which is then further heated in an atmosphere of the reactive gas: in the former case first oxygen, then ammonia p  may be introduced so that the oxide formed is at least partially converted into nitride.  The base plate may be of high melting point glass; in order to coat only a part thereof with the conducting film, either the base is first painted with a masking composition where the film is not wanted, or the entire base is coated and unwanted film then removed by chemical action of zinc and hydrochloric acid.  An annular track for a sliding contact potentiometer may be so produced.