| abstract |
A microwave plasma generating apparatus ( 10 ) has a microwave cavity ( 20 ) coupled to a microwave source ( 22 ) by a wave guide ( 24 ). Within the cavity (20) is a reaction tube ( 30 ) defining a plasma cavity ( 40 ). A gas inlet manifold ( 50 ) is provided at the top of the reaction tube ( 30 ), which is formed so as to introduce plasma gas tangentially to the longitudinal axis of the plasma. Plasma gas is thus injected into the reaction tube ( 30 ) so that it flows in a swirled manner, that is, in the form of a vortex. This prevents overheating of the reaction tube ( 30 ). |