| 摘要 |
The invention provides new methods and apparatus for the deposition of materials on substrates by the use of a D.C. glow discharge, sometimes also called a plasma discharge. A precursor gas (or gases), which is a decomposable compound of the required material, is introduced at low pressure (10-500 milliTor) into an enclosure containing two spaced parallel cathode electrodes and an intermediate parallel anode electrode, preferably midway between the two cathodes. Upon the application of a suitable positive potential to the anode a deposition plasma is generated in the space on both sides of the anode, primarily it is believed by electrons that oscillate back and forth through the anode, giving an increased free path for collisions and rendering the dissociation process more efficient. The plasma of charged and neutral radicals moves to the cathodes both by charge attraction and by diffusion, giving high quality films at increased deposition rates, higher possible discharge current densities, lower gas pressures with consequent gas economy and safety, improved film adhesion, and greater independence of these parameters from one another than has been possible with the prior art processes. To avoid encroachment of the plasma on the cathodes and substrates supplementary cathode electrodes may be interposed between the first-mentioned cathodes and the anode close to the former, so that the plasma is confined between the supplementary cathodes.
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