GB1328838A - Vapour reaction apparatus - Google Patents

Abstract

1328838 Depositing by reaction from vapour; apparatus INTERNATIONAL BUSINESS MACHINES CORP 22 Dec 1970 [2 Jan 1970] 60726/70 Heading C7F [Also in Division C1] A vapour reaction apparatus includes a tubular reaction chamber, a gas inlet distribution baffle extended across substantially the whole cross-sectional area of one end of the chamber and providing sufficient resistance to gaseous phase material to develop a substantially uniform back pressure and to deliver a substantially uniform flow of gas with a planar velocity front over substantially the whole crosssection of the chamber, and a gas exit pressure baffle extending across substantially the whole area of the other end of the chamber to provide uniform gas resistance thereover. The apparatus may be used for the reduction of silicon tetrafluoride by hydrogen. In the Figure is shown a vapour deposition reactor 10 comprising an opaque quartz cylinder 12 capped at both ends by hollow plates 14 and 16 made of stainless steel through which cooling water may be circulated and defining a reaction chamber 18. The reaction chamber may be 9 inches in diameter and 18 inches high. Tie rods 20, with the aid of O-rings 22 and 24 enable the chamber 18 to be made air-tight. The lower plates 16 and O-ring 24 are attached to a hydraulic cylinder which opens and closes the reactor. In the chamber 18 is a substrate holder, graphite susceptor 28, mounted on a fusedquartz rod 26, having mounted around its circumference and substantially parallel to the longitudinal axis of the chamber defined by rod 26 a plurality of substrates 30 upon which the deposition is desired. The susceptor may be mounted on the rod 26 by a star plate. Supported by the top plate 14 and extending the whole of the cross-section of the chamber there is provided a gaseous phase inlet means including a distribution baffle 38, which forms with the plate 14 a first plenum 36. Gaseous materials 32 are introduced through tube 34 to 36 and are evenly delivered over the whole of the crosssectional area of the reaction chamber 18. The gas distribution baffle 38 may be a perforated plate or a sintered material having a gas resistance sufficient to develop uniform back pressure to maintain even gas distribution over the entire surface area of the baffle. A heat shield 40 may be mounted on the reaction chamber outside the baffle 38 to reflect the radiation from the heat receptor 28. 40 is a thin plate of stainless steel or molybdenum. Gaseous materials having passed through the heat shield 40 enter chamber 18 having a planar velocity front. After passing over the susceptor 28 reactant gases leave the bottom of the chamber through an exit pressure baffle 42 also of sintered or porous material. Preferably, the porosity of baffle 42 is greater than that of baffle 38. Exhaust gases pass through the second plenum 48 and exhaust tubes 50 to the atmosphere or to a reclamation process. To heat the substrate an RF source is preferred although a resistance heater may be used.