US 4,882,199 A · Method of forming a metal coating on a substrate

Abstract

A method for producing a uniform metal coating on a substrate consisting of (1) selecting one or more metals to be coated onto the substrate wherein the metals are soluble in a molten salt when heated, (2) preparing a bath consisting of the dissolved metal-molten salt, (3) inserting a substrate into the bath, and (4) decreasing the temperature at the substrate to a level at which the metal will precipitate out of solution onto the substrate. Multiple coatings can be made by repeating the method using the same or different metal-molten salt systems. Deposition can be enhanced by adding more salt to the bath to increase precipitation of the metal onto the substrate or by introducing additional metal into the bath by electrolysis, either by electrowinning or electrorefining. The metal coating can be patterned by localized heating of the metal coating in the metal-molten salt bath to reverse deposition or by masking areas on the substrate prior to deposition. The method can also be used to purify the metal or compound being precipitated by controlling the composition and processing parameters of the metal-molten salt bath. Alternatively, these same parameters can be controlled to deposit metals or compounds containing desired levels of specific impurities such as in the case of doped GaAs.

Claims21

Dependent claims

A method for producing a metal coating on a substrate comprising:

(a) selecting a first metal to be coated onto the substrate wherein said metal is soluble in a molten salt when heated to a first temperature, said metal and molten salt being selected from the group consisting of Mn-MnCl.sub.2 /NaCl, Ag-AgCl/NaCl, Mo-K.sub.3 MoCl.sub.6 /KCl, Mg-MgCl.sub.2, Ca-CaCl.sub.2, Al-Na.sub.3 AlF.sub.6, Na-NaCl, Si-K.sub.2 SiF.sub.6 /KF, Ta-TaCl.sub.5, Cd-CdCl.sub.2, Cu-CuCl.sub.2, Sr-SrCl.sub.2, Ba-BaCl.sub.2, Y-YF.sub.3, Sc-ScF.sub.3, Bi-BiCl.sub.3, Al-AlCl.sub.3 /KCl, Au-AuCl.sub.3, Au-Au(CN).sub.2, lanthanide series metals-lanthanide salts, and actinide series metals-actinide salts,
(b) heating a bath of said metal and molten salt to the first temperature to dissolve said metal,
(c) placing the substrate to be coated in the bath, and
(d) decreasing the temperature of the bath at the substrate to a second temperature, wherein the dissolved metal precipitates out of the molten salt onto the substrate at the second temperature.

1 more element

Dependencies are inferred from the claim text.

Method of forming a metal coating on a substrate

Life of this patent

Method of forming a metal coating on a substrate

Life of this patent

Abstract

Claims21