International Business Machines Corporation

Bruce Bumble

Jerome J Cuomo

Kevin K Chan

Joseph S Logan

Joseph M Blum

William Francis Kane

Joao R Conde

Steven M Rossnagel

A high-efficiency, low-temperature, plasma-enhanced chemical vapor deposition (PECVD) system for growing or depositing various types of thin films on substrate surfaces, or etching such surfaces, using substrates of materials such as silicon, plastic, etc. The system uses a hollow-cathode-effect electron source with a surrounding confining electrode to create a plasma at the substrate surface to insure that the density of reactive species is both enhanced and localized at the substrate surface thus causing the rate of growth of the films, or the etch rate, to increase so that the process can take place at much lower temperatures and power levels. A particular embodiment involves the growing of hydrogenated amorphous silicon (a:Si:H), at room temperature, on silicon using a tubular reactor containing a cylindrical electrode lining the inside of the reactor walls acting as a counter electrode for an rf-powered, substrate-supporting electrode near the center of the reactor. A set of silicon wafers, on which the amorphous silicon is grown, is mounted on the latter electrode. The reaction gases (silane) flowing between the electrodes are decomposed in a plasma excited by an rf power source (13.56 MHz) connected to the substrate-supporting electrode. With the use of appropriate deposition parameters (silane flow rate, pressure, applied power and frequency, and substrate spacing) room temperature growth of a-Si:H is achieved at growth rates up to 15 .ANG./sec, while keeping a low hydrogen concentration (.about.10%) and the bonded hydrogen in the Si-H monohydride configuration.

Plasma enhanced chemical vapor processing system using hollow cathode

A metallic hollow cathode electrode structure for use in a RF-RIE sputter/etch system. The electrode defines a critical aspect ratio hollow cathode volume. In accordance with one embodiment of the invention, the electrode structure may consist of two closely spaced metal elements separated by a distance of a few centimeters. The elements are electrically and structurally connected by supports around their outer rim. An RF voltage is applied between the improved hollow cathode electrode structure and an evacuated chamber containing same through a suitable matching network. A plasma gas is supplied to the system from a point outside the electrodes and a suitable pumping system is used to maintain operating pressures in the 0.1 to 400 millitorr range. Samples to be sputtered are then placed on either of the inside electrode surfaces for sputter/etching. The aspect ratio (longest dimension of one of the elements/spacing between the elements) should be at least 4. According to a further embodiment, the hollow cathode electrode structure is characterized by a single plate having a plurality of cylindrical chambers or holes therein, each hole producing a hollow cathode glow when the system is energized. The aspect ratio (largest dimension of the chamber cross-section/depth of the chamber) for this embodiment should be at least 1.5.

Hollow cathode enhanced plasma for high rate reactive ion etching and

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Pasadena, CA, United States of America

Bruce Bumble