Abstract: A method and apparatus are described for removing arsine from a gaseous stream such as the gaseous effluent stream from an MOCVD operation in which arsine is employed as an arsenic source. The arsine is burned in the gas phase in the presence of oxygen (air) to form arsenic oxide and a gaseous effluent stream in which all or part of the arsenic oxide is entrained. The arsenic oxide is removed from this stream by washing the same with an aqueous stream thereby forming an aqueous solution of arsenic oxide. At least a portion of this aqueous solution is recirculated to the aqueous spray so that a progressively enriched aqueous solution of arsenic oxide is formed. Periodically an insoluble arsenic containing compound is precipitated from the solution before it becomes saturated with arsenic oxide. Thus, arsine is eliminated from gaseous streams and converted into harmless forms which can be readily handled and disposed of without harm to the environment.

Abstract: Chemical vapor deposition apparatus has a quartz envelope supporting a resistance heater. A boron nitride pill box configured core supports resistance heater windings. The core has a base having a cylindrical upper portion defining a hollow chamber and an upper annular ring. A circular top includes an upper circular portion and lower circular portion mating with the base. The annular ring surface is in thermal contact with the upper circular portion to transfer heat from the annular ring to the circular top. A zirconia insulator cups the core, providing heat insulation, in conjunction with a heat shield coating in the quartz envelope interior. Arrays of quartz envelope heaters provide for mass production of semiconductors. A horizontal configuration includes a laminar flow head and disposed at an angle to the horizontal.

Abstract: A system is described enabling the flow of gaseous substances to be altered or switched from one line to another as desired without need for lubricants or having parts in continuous frictional contact with each other. In essence, the system is composed of (a) a first chamber having a gas entry port, and a pair of gas exit ports; (b) a second chamber adapted to receive gas flowing through one of the exit ports, and additionally having a gas discharge port and a separate gas inlet port to receive another flow of gas; (c) a third chamber adapted to receive gas flowing through the other of the exit ports, and additionally having a gas discharge port and a separate gas inlet port to receive another flow of gas; and (d) an internal valve for alternatively sealing off one or the other of the gas exit ports. Preferably, the valve is magnetically actuated by means of a sub-system which is itself pneumatically actuated. The advantage of using the system in MOCVD are described.