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 . <EOS>