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Combustion Furnace for the Removal of Light Hydrocarbons from Oxidizing Gases

IP.com Disclosure Number: IPCOM000080225D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Irene, EA: AUTHOR

Abstract

Oxygen with a hydrocarbon content which corresponds to 20-30 ppm water can be purified to 2-3 ppm water. The thickness control and physical properties of the films of Si0 on Si are largely dependent on the overall cleanliness and quality of the oxygen used to prepare the oxide. Small amounts of water in the oxygen is generally believed to accelerate the rate of SiO(2) growth on silicon (Si). Variable quantities of water will render the oxide growth process irreproducible.

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Combustion Furnace for the Removal of Light Hydrocarbons from Oxidizing Gases

Oxygen with a hydrocarbon content which corresponds to 20-30 ppm water can be purified to 2-3 ppm water. The thickness control and physical properties of the films of Si0 on Si are largely dependent on the overall cleanliness and quality of the oxygen used to prepare the oxide. Small amounts of water in the oxygen is generally believed to accelerate the rate of SiO(2) growth on silicon (Si). Variable quantities of water will render the oxide growth process irreproducible.

A liquid oxygen source in conjunction with clean and air tight plumbing is typically utilized as the source of gaseous oxygen. Such a system will reduce the water content of gaseous oxygen to levels around 1-5 ppm. However, in addition to water impurity, there are also light hydrocarbons present in the boil-off from liquid oxygen such as CH(4) and C(2)H(6). At typical oxidation temperatures greater than 400 degrees C, the hydrocarbons will be combusted to water (H(2)O) and carbon dioxide (CO(2)). The H(2)O produced then adds to the H(2)O already present and thereby has detrimental effects on the desired oxide growth. A technique is described herein for removing hydrocarbon impurites and enabling the reproducible preparation of desired oxide thicknesses.

Hydrocarbons can be combusted in oxygen at elevated temperatures and the efficiency of the combustion process is a function of total hydrocarbon concentration, temperat...