At&t Bell Laboratories

At&t Ipm Corp.

Eray S Aydil

Richard A Gottscho

Konstantinos P Giapis

Zhen-Hong Zhou

Mark A Jarnyk

Jeffrey A Gregus

Applicants have discovered that gallium arsenide surfaces can be dry passivated without heating or ion bombardment by exposing them downstream to ammonia plasma formation. Specifically, a workpiece having exposed gallium arsenide surfaces is passivated by placing the workpiece in an evacuable chamber, evacuating in the chamber, generating an ammonia plasma removed from the immediate vicinity of the workpiece, and causing the plasma products to flow downstream into contact with the workpiece. Preferably the plasma gas pressure is 0.5 to 6.0 Torr, the substrate temperature is less than 100.degree. C. and the time of exposure is in excess of 5 min. The plasma should be generated at a location sufficiently removed from the workpiece that the workpiece surface is not bombarded with ions capable of damaging the surface (more than about 10 cm) and sufficiently close to the workpiece that reactive plasma products exist in the flow (within about 30 cm). The workpiece should also not be placed within line-of-sight of the plasma to avoid radiation (UV, visible and X-ray) induced damage. The result is fast, stable, room temperature passivation, compatible with clustered dry processing techniques for integrated circuit manufacture.

Downstream ammonia plasma passivation of GaAs

A novel vapor phase Si cleaning process comprises simultaneous exposure of the Si surface to a flux of neutral atomic hydrogen and to a flux of ionized particles. The former flux is substantially derived from a plasma, typically a microwave plasma, that is spaced apart from a second plasma, typically a RF plasma, from which the ionized particles are derived. The novel method can be implemented at relatively low cost and facilitates adjustment of the ratio between the two fluxes to result in optimal removal of, e.g., native oxide from the surface.

Method of making a silicon-based device comprising surface plasma

In accordance with the invention, a plasma generated within a plasma confinement chamber for use in manufacturing semiconductor devices is controlled by monitoring both the neutral gas pressure P and the neutral gas temperature T. The process parameters P and T are then adjusted to control P/T.sup.n. In a preferred embodiment the pressure is adjusted to maintain P/T constant by adjusting the gas flow rate or the outlet pumping speed. The result is a plasma exhibiting enhanced stability over prolonged periods of time.

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Summit, NJ, United States of America

Eray S Aydil