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Process for Producing a Random Array of Small Metal Spheres

IP.com Disclosure Number: IPCOM000046107D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Alessandrini, EI: AUTHOR [+5]

Abstract

A method is described for depositing a random array of small spheres on a substrate. This coating may be used, for example, as an optical absorption layer, an adhesion improving layer, a scanning electron microscope (SEM) standard or an etch mask for texturing polymers.

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Process for Producing a Random Array of Small Metal Spheres

A method is described for depositing a random array of small spheres on a substrate. This coating may be used, for example, as an optical absorption layer, an adhesion improving layer, a scanning electron microscope (SEM) standard or an etch mask for texturing polymers.

A random array of small gold spheres with a diameter between 10 nm and 50 nm has been fabricated by evaporating a 2-6 nm thick film of Au, Pd, or Pt onto a Si3N4 or TiO2 substrate and annealing the film for 3 hours at 400 to 550OEC in hydrogen. The thinner the film, the smaller and closer spaced are the spheres.

The structure of small spheres is the stable configuration, but energy must be supplied to enable the atoms in the film to become mobile. This energy can be provided many different ways: a. The film and substrate can be directly heated.

b. The film can be exposed to an ion beam instead.

This may be done in selective areas, if desired.

c. The film can be exposed to an electron beam

instead of an ion beam.

d. The film can be exposed to a laser or other light

beam instead of an ion or electron beam.

Methods b, c, and d will add energy mainly to the surface without significant heating of the substrate.

If the coagulation of the metal is to proceed easily:

a. the substrate material should be chosen or treated

so as to have a weak interaction with the metal

film, and

b. gas such as hydrogen, or a suitable liquid, might

be used to reduce...