A substrate processing chamber, comprising: a chamber body; a chamber lid assembly having a housing enclosing a funnel shaped gas dispersion channel that extends along a central axis and has an upper portion and a lower portion; a gas delivery system configured to provide two or more gases to the gas dispersion channel; a lid plate coupled to the housing and having a contoured lower surface that is downwardly sloping to extend downwardly and outwardly from a central opening coupled to the lower portion of the funnel shaped gas dispersion channel to a peripheral portion of the lid plate; and a gas distribution plate disposed below the lid plate and having a plurality of apertures disposed through the gas distribution plate wherein the contoured lower surface of the lid plate extends to and contacts the gas distribution plate, such that the gas distribution plate extends to a surface of the gas dispersion channel such that the only pathway from the gas dispersion channel to the substrate is through the plurality of apertures of the gas distribution plate; and a remote plasma source RPS fluidly coupled to the gas dispersion channel; a cleaning gas source fluidly coupled to the RPS; and an isolation collar coupled between the remote plasma source and the housing, the isolation collar has an inner channel extending through the isolation collar to fluidly couple the remote plasma source and the gas dispersion channel, wherein an exhaust system having an exhaust conduit is coupled to the isolation collar. a chamber body; a chamber lid assembly having a housing enclosing a funnel shaped gas dispersion channel that extends along a central axis and has an upper portion and a lower portion; a gas delivery system configured to provide two or more gases to the gas dispersion channel; a lid plate coupled to the housing and having a contoured lower surface that is downwardly sloping to extend downwardly and outwardly from a central opening coupled to the lower portion of the funnel shaped gas dispersion channel to a peripheral portion of the lid plate; and a gas distribution plate disposed below the lid plate and having a plurality of apertures disposed through the gas distribution plate wherein the contoured lower surface of the lid plate extends to and contacts the gas distribution plate, such that the gas distribution plate extends to a surface of the gas dispersion channel such that the only pathway from the gas dispersion channel to the substrate is through the plurality of apertures of the gas distribution plate; and a lid plate coupled to the housing and having a contoured lower surface that is downwardly sloping to extend downwardly and outwardly from a central opening coupled to the lower portion of the funnel shaped gas dispersion channel to a peripheral portion of the lid plate; and a gas distribution plate disposed below the lid plate and having a plurality of apertures disposed through the gas distribution plate wherein the contoured lower surface of the lid plate extends to and contacts the gas distribution plate, such that the gas distribution plate extends to a surface of the gas dispersion channel such that the only pathway from the gas dispersion channel to the substrate is through the plurality of apertures of the gas distribution plate; and a remote plasma source RPS fluidly coupled to the gas dispersion channel; a cleaning gas source fluidly coupled to the RPS; and an isolation collar coupled between the remote plasma source and the housing, the isolation collar has an inner channel extending through the isolation collar to fluidly couple the remote plasma source and the gas dispersion channel, wherein an exhaust system having an exhaust conduit is coupled to the isolation collar.