Patent ID: 8252114
Filing Date: 2012-08-28
Classification: C23C

Abstract:
1. A gas distribution system configured to be coupled to or within a process chamber for depositing a layer on a substrate, the gas distribution system comprising: a housing including an inlet and an outer circumferential edge; a vapor distribution plate coupled to the housing to define a plenum between the inlet and the vapor distribution plate, the vapor distribution plate including a plurality of orifices for distributing a process gas from the plenum to a process space above said substrate; and a solid plate-shaped piston disposed in the plenum having continuous upper and lower surfaces that prevent gas flow therethrough to define a flow path for the process gas that extends around the solid plate-shaped piston from the inlet to an upper plenum portion between the solid plate-shaped piston and the outer circumferential edge of the housing and to a lower plenum portion between the solid plate-shaped piston and the vapor distribution plate; wherein the solid plate-shaped piston is vertically moveable from an upper position to a lower position in which the process gas flows around the solid plate-shaped piston and through the plurality of orifices with the relative flow through an outer radial portion of the plurality of orifices versus through a central radial portion of the plurality of orifices being uniform in one of the upper or lower positions and non-uniform in the other of the upper and lower positions.