|Publication number||USH1396 H|
|Application number||US 08/125,050|
|Publication date||Jan 3, 1995|
|Filing date||Sep 21, 1993|
|Priority date||Sep 21, 1993|
|Publication number||08125050, 125050, US H1396 H, US H1396H, US-H-H1396, USH1396 H, USH1396H|
|Inventors||John R. Vig, Mary A. Hendrickson, Sally M. Laffey|
|Original Assignee||The United States Of America As Represented By The Secretary Of The Army|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (11), Classifications (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalties thereon.
The invention relates in general to the art of coating an oxide surface or substrate with a gold film and in particular to a method of depositing a strongly adhering gold film onto a quartz substrate and to the gold film so deposited.
It has been well known that gold films do not adhere to oxide surfaces, such as quartz. For example, the generally accepted criterion for adhesion between a metal film and an oxide surface or substrate has been that the metal must be oxygen active so as to react chemically with the oxide surface. Since gold does not form a stable oxide under normal conditions, having a heat of oxide formation of +19 kcal/mol it, supposedly, does not adhere to oxide surfaces as, for example, quartz. Adhesion layers, such as chromium or titanium are often used as adhesion layers between the oxide and the gold. In some cases, however, it would be highly desirable to not have to use an intermediate layer.
The general object of this invention is to provide a gold film that will strongly adhere to an oxide surface. A more particular object of the invention is to provide such a gold film without an intermediate adhesion layer. A particular object of the invention is to provide such a gold film for a quartz surface or substrate.
It has now been found that an adherent gold film can be deposited on an oxide surface or substrate by cleaning the oxide surface so as to remove all organic contaminants and then vacuum depositing onto the clean oxide surface a gold film of up to 40 nanometers in thickness.
Gold films of thickness 10 nm, 20 nm and 30 nm adhere strongly, whereas films of greater than 40 nm thickness adhere very weakly. In this connection, the Scotch tape test readily removes the thicker films but not the thinner ones.
The surface of a quartz substrate is first cleaned and all organic contaminants removed by standard UV-ozone technique such as described in U.S. Pat. No. 4,028,135 by Vig et al.
The cleaned quartz substrate is placed into an ultrahigh vacuum system. A gold film is then vacuum deposited by a clean deposition method such as thermal evaporation or electron beam deposition. The thickness of the film is in the range of 10 to 30 nanometers.
The film adheres very strongly as evidenced by the fact that it cannot be removed by the Scotch tape test, or by ultrasonic agitation in water, alcohol or acetone, or by mechanical abrasion with objects such as cleanroom wipes, sponge tips and wooden sticks. In lieu of quartz one can use any substrate with an oxide surface, such as silicon wafers, glass and aluminum oxide.
We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3653946 *||Sep 30, 1969||Apr 4, 1972||Bell Telephone Labor Inc||Method of depositing an adherent gold film on the surfaces of a suitable substrate|
|US3833410 *||Dec 30, 1971||Sep 3, 1974||Trw Inc||High stability thin film alloy resistors|
|US4005229 *||Jun 23, 1975||Jan 25, 1977||Ppg Industries, Inc.||Novel method for the rapid deposition of gold films onto non-metallic substrates at ambient temperatures|
|US4028080 *||Jun 23, 1976||Jun 7, 1977||The United States Of America As Represented By The Secretary Of The Army||Method of treating optical waveguide fibers|
|US4309460 *||Oct 14, 1980||Jan 5, 1982||Bell Telephone Laboratories, Incorporated||Process for producing gold films|
|US4457972 *||Dec 7, 1981||Jul 3, 1984||California Institute Of Technology||Enhanced adhesion by high energy bombardment|
|US4888204 *||Sep 12, 1988||Dec 19, 1989||Hughes Aircraft Company||Photochemical deposition of high purity gold films|
|US4933204 *||Sep 23, 1988||Jun 12, 1990||Rockwell International Corporation||Method of producing a gold film|
|US4959257 *||Jul 12, 1988||Sep 25, 1990||Lucas Industries Public Limited Company||Transparencies|
|US5139856 *||Dec 20, 1989||Aug 18, 1992||Ngk Insulators, Ltd.||Plated ceramic or glass substrate having undercoat|
|US5288558 *||Sep 11, 1992||Feb 22, 1994||Flachglas Aktiengesellschaft||Attachment for video screens having dual optical active dereflection layers|
|U.S. Classification||429/122, 429/199|