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Color Indicator for III/V Surface Cleanliness and Oxide Removal

IP.com Disclosure Number: IPCOM000078924D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Feeley, JD: AUTHOR [+4]

Abstract

Varying the concentration of an etchant and cleaning compound for gallium arsenide wafers provides a cleaning process which is noncontaminating, repeatable, enhances alloying of contact metallurgy, and indicates the degree to which a contact hole opening has been made in an oxide coating on the wafer.

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Color Indicator for III/V Surface Cleanliness and Oxide Removal

Varying the concentration of an etchant and cleaning compound for gallium arsenide wafers provides a cleaning process which is noncontaminating, repeatable, enhances alloying of contact metallurgy, and indicates the degree to which a contact hole opening has been made in an oxide coating on the wafer.

A gallium arsenide wafer coated with a silicon dioxide coating may be etched and cleaned by a sodium oxychloride etching process, followed by a sodium oxychloride plus sodium carbonate cleaning solution. The etching and cleaning is described by the following equations:
GaAs + NaClO GaAsO(3) (arsenite) + salt GaAsO(3) + NaClO GaAsO(4) (self-limiting reaction turns surface black)

GaAsO + Na(2)Co(3) + NaClO GaAs + Soluble Salt.

The concentration of the sodium oxychloride staining solution is 0.53 moles. When this concentration is used, the gallium arsenide surface will indicate a light brown stain when the oxide coating has been etched. The concentration of the sodium oxychloride and sodium carbonate cleaning solution are 0.8 moles and
0.4 moles, respectively.

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