Method of depositing electrically conductive, infra-red reflective, transparent coatings of stannic oxide
OwnerRoy G. Gordoninventor
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Abstract
Electrically-conductive films of tin oxide are prepared by a novel process utilizing gaseous chemical compounds which react to form a tin-fluorine bond at a temperature which is (1) high enough so that the newly-created tin-fluorine bond-bearing molecule remains in the vapor phase; and (2) low enough so that oxidation of the molecule occurs only after the indicated re-arrangement. Films prepared by the process of the invention are characterized by surface resistances as low as 1 ohm per square when the film thickness is as thin as about a micron. These films are also characterized by extremely good reflectance of infrared radiation.
Claims47
A process for making transparent films of stannic oxide on a heated substrate using a gaseous mixture initially containing
- (1) a first organotin fluorine-bearing compound which is free of any direct tin-fluorine bond
- (2) a oxidizable, tin compound, and
- (3) an oxidizing gas said process comprising the steps of:
- (a) converting said first organotin fluorine-bearing component of said gaseous mixture into a second organotin fluoride gaseous compound having a direct tin-to-fluorine bond;
- (b) immediately oxidizing, in immediate proximity to said substrate, the second fluoride compound to obtain a fluorine dopant in the gaseous mixture;
- (c) and forming a fluorine doped stannic oxide film, on said heated substrate, by simultaneous deposition thereon of said oxidizable tin compound and said fluorine dopant.
A process for depositing transparent, fluorine-doped, tin-oxide films, on a heated substrate said process comprising the steps of
- (1) supplying a continuous stream of a reagent gas to the vicinity of said substrate, said reagent gas containing reagents which are convertible to an organotin fluoride compound having a direct tin-fluorine bond in the immediate proximity of said heated substrate, and
- (2) depositing said organotin fluoride compound with an oxidizable tin component of said reagent gas at the surface of said gas and thereby achieving a fluorine-doped, tin oxide coating upon said surface.
A process for depositing films of fluorine-doped stannic oxide on a heated substrate, said process comprising mixing
- (a) a gaseous, fluorine-bearing component, and
- (b) a gaseous, oxidizable tin-bearing component, and
- (c) a gaseous, oxygen-bearing component, and, optionally,
- (d) inert carrier gas these components being selected so that they remain in the gas phase at the temperature of mixing and wherein component (a) forms a compound with a tin-fluorine bond only as the gas mixture is heated to about the temperature of said heated substrate, said compound with a tin-fluorine bond and said oxygen bearing component then reacting to deposit said film of fluorine-doped stannic oxide on said heated substrate, and wherein said component (a) contains a volatile organotin fluorine-bearing compound which is free of any direct tin-fluorine bond but which rearranges on heating to form a direct tin-fluorine bond at temperatures high enough so that the newly-formed compound with a direct tin-fluorine bond remains in the vapor phase until it reacts along with the oxidizable tin compound to deposit a film of fluorine-doped tin oxide.
A process for depositing films of fluorine-doped stannic oxide on a heated said process comprising mixing
- (a) a gaseous, fluorine-bearing component, and
- (b) a gaseous, oxidizable tin-bearing component, and
- (c) a gaseous, oxygen-bearing component, and, optionally,
- (d) inert carrier gas these components being selected so that they remain in the gas phase at the temperature of mixing and wherein component (a) and component (b) react to form a compound with a tin-fluorine bond only as the gas mixture is heated to about the temperature of said heated substrate, said compound with a tin-fluorine bond and said oxygen bearing component then reacting to deposit said film of fluorine-doped stannic oxide on said heated substrate in which component (a) contains reactive fluoroalkyl groups and in which component (b) contains an organometallic tin compound.
A process for depositing films of fluorine-doped stannic oxide on a heated substrate said process comprising mixing
- (a) a gaseous, fluorine-bearing component, and
- (b) a gaseous, oxidizable tin-bearing component, and
- (c) a gaseous, oxygen-bearing component, and, optionally,
- (d) inert carrier gas these components being selected so that they remain in the gas phase at the temperature of mixing and wherein component (a) and component (b) react to form a compound with a tin-fluorine bond only as the gas mixture is heated to about the temperature of said heated substrate, said compound with a tin-fluorine bond and said oxygen bearing component then reacting to deposit said film of fluorine-doped stannic oxide on said heated substrate;
- in which component (a) contains reactive fluorosulfur groups;
- and in which component (b) contains an organometallic tin compound.
A process for depositing films of fluorine-doped stannic oxide on a heated substrate said process comprising mixing
- (a) a gaseous, fluorine-bearing component, and
- (b) a gaseous, oxidizable tin-bearing component, and
- (c) a gaseous, oxygen-bearing component, and, optionally,
- (d) inert carrier gas these components being selected so that they remain the gas phase at the temperature of mixing and wherein component (a) and component (b) react to form a compound with a tin-fluorine bond only as the gas mixture is heated to about the temperature of said heated substrate, said compound with a tin-fluorine bond and said oxygen bearing component then reacting to deposit said film of fluorine-doped stannic oxide on said heated substrate;
- in which component (a) contains reactive fluorosulfur groups selected from SF.sub.5 Cl, SF.sub.5 Br, or SF.sub.5 CF.sub.3, and homologous or substituted compounds of mixtures thereof;
- and in which component (b) contains organometallic tin compound.
Dependencies are inferred from the claim text.