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Fabrication of Aluminum Oxide Films

IP.com Disclosure Number: IPCOM000098019D
Original Publication Date: 1961-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

DaSilva, EM: AUTHOR [+2]

Abstract

The apparatus fabricates thin insulating layers in micro-miniature electrical circuits, in which it is not required to evaporate the oxide itself. Rather, the oxide is directly formed in the gas phase, through the evaporation of metallic aluminum in an oxygen environment.

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Fabrication of Aluminum Oxide Films

The apparatus fabricates thin insulating layers in micro-miniature electrical circuits, in which it is not required to evaporate the oxide itself. Rather, the oxide is directly formed in the gas phase, through the evaporation of metallic aluminum in an oxygen environment.

Current is supplied to a pair of heater terminals connected through a vacuum chamber. A tungsten heater filament is coupled between the pair. Supported upon a recess in the filament is an aluminum evaporant charge. Resistive heating of the filament is sufficient to raise the charge to evaporation temperature. The vaporized particles are directed towards the surface of the substrate. Positioned adjacent to the substrate is a nozzle through which is directed a stream of oxygen at a predetermined pressure. The vaporized aluminum interacts with the gaseous oxygen in the vicinity of the substrate, the resultant aluminum oxide being deposited on it.

The position of the oxygen inlet is important for two reasons. First, the closer to the substrate the higher the effective oxygen pressure in the area of the film and hence the more effective the oxidation reaction should be. Secondly, the efficient use of oxygen at the film allows lower partial pressures in the rest of the system, particularly at the source, where the rate of evaporation is sensitive to oxidation. In fact, experiment has shown that there is an ideal compromise to be exploited in the correct positioning...