| 摘要 |
<p>A thermal control system e.g. for a PECVD (Plasma Enhanced Chemical Vapour Deposition) system comprising an energy source and a gas delivery system (fig. 3) including gas ratio control means for introducing a gas mixture between a substrate and a substrate holder 105 to control thermal coupling. A radiation detector e.g. a pyrometer (111, fig. 1) for measuring radiation emitted from a layer deposited on a silicon substrate is located on the opposite side of the substrate holder 105 to the substrate. The silicon substrate is at a temperature such that it is transparent at a selected frequency of electromagnetic radiation. A second electrode (123, fig. 4a) comprising openings e.g. a molybdenum mesh is located between a first electrode (the substrate holder 105) and a heat source e.g. UV, IR or optical lamps 116, The size of the openings may depend on the power supply frequency. Gas feed tube 120b is in thermal contact with heat source 116 to pre-heat process gases. A metal catalyst (703, fig. 7) is heated on the substrate in oxygen to provide a controlled oxide layer around metal islands before preparing carbon nanotubes in the PECVD system.</p> |
