Research Triangle Institute

George Carlton Hudson

Ronald A Rudder

Robert C Hendry

Robert J Markunas

Michael J Mantini

Robert Carlisle Hendry

A method and apparatus for generating plasmas adapted for chemical vapor deposition, etching and other operations, and in particular to the deposition of large-area diamond films, wherein a chamber defined by sidewalls surrounding a longitudinal axis is encircled by an axially-extending array of current-carrying conductors that are substantially transverse to the longitudinal axis of the chamber, and a gaseous material is provided in the chamber. A high-frequency current is produced in the conductors to magnetically induce ionization of the gaseous material in the chamber and form a plasma sheath that surrounds and extends along the longitudinal axis and conforms to the sidewalls of the chamber. A work surface extending in the direction of the longitudinal axis of the chamber is positioned adjacent a sidewall, exposed to the plasma sheath and treated by the plasma. Preferably, the ratio of the width to the height of the chamber is 10:1 or larger so that the chamber includes a large area planar surface adjacent the plasma sheath and adjacent to which a large area substrate or a plurality of substrates is arranged, whereby large area treatment, such as diamond deposition, can be performed.

Plasma treatment apparatus

Plasma treatment method for treatment of a large-area work surface

A chemical vapor deposition (CVD) process and apparatus for the growth of diamond films using vapor mixtures of selected compounds having desired moieties, specifically precursors that provide carbon and etchant species that remove graphite. The process involves two steps. In the first step, feedstock gas enters a conversion zone. In the second step, by-products from the conversion zone proceed to an atomization zone where diamond is produced. In a preferred embodiment a feedstock gas phase mixture including at least 20% water which provides the etchant species is reacted with an alcohol which provides the requisite carbon precursor at low temperature (55.degree.-1100.degree. C.) and low pressure (0.1 to 100 Torr), preferably in the presence of an organic acid (acetic acid) which contributes etchant species reactant. In the reaction process, the feedstock gas mixture is converted to H.sub.2, CO, C.sub.2 H.sub.2, no O.sub.2, with some residual water. Oxygen formerly on the water is transferred to CO. Hence, an etchant species (H.sub.2 O, OH, O) is replaced in the reactor by CO, a growth species and prevents undesirous consumption of diamond (the net-product). In a preferred embodiment, the apparatus assures conversion by preventing gas circumvention of the conversion zone prior to dissociation in the hydrogen atomization zone to produce the necessary atomic hydrogen for diamond growth.

Process and apparatus for chemical vapor deposition of diamond films

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Clayton, NC, United States of America

George Carlton Hudson