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Long Life Gold Based Optical Storage Materials

IP.com Disclosure Number: IPCOM000044966D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 118K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+2]

Abstract

The relatively short life of gold island films for optical storage is extended by the addition of an amorphous silicon overcoat.

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Long Life Gold Based Optical Storage Materials

The relatively short life of gold island films for optical storage is extended by the addition of an amorphous silicon overcoat.

Thin discontinuous gold (Au) films less than 3 nm thick including island structures are useful for an optical storage material. However, these films have a limited life, especially at elevated temperatures. For example, when such films are examined with a transmission electron microscope, the small gold islands merge with large islands with a slight increase in sample temperature, caused by either electron beam heating or other heating. This change is accompanied by changes in optical reflectivity and absorption.

Here, we use the same gold-island structure for optical recording, with an overcoat of a very thin amorphous film of silicon (Si) in the thickness range of 2 to 10 nm. In such a bilayer structure, the gold migration is eliminated completely, as demonstrated in TEM results. Furthermore, other useful features are obtained in the bilayers. The Si layer increases the optical absorption to increase the optical efficiency. Fig. 1 compares the optical absorption of a single Au-island film and two bilayers with different gold and amorphous Si films. Laser writing energy is compared for the time durations in the table for these films. Although the bilayer includes more mass to be heated during the writing process, as it has a higher optical efficiency, it requires less energy than the singl...