A showerhead disperser device for mixing plural vapor streams, comprising: a housing including front and rear walls in spaced apart relation to one another, and a side wall therebetween, defining within the housing an interior volume; the front wall having a multiplicity of vapor mixture discharge openings therein, for discharging mixed vapor from the interior volume of the housing exteriorly thereof, flow passages joined to the housing for introducing into the interior volume of the housing respective fluids to be mixed therein; and at least one baffle plate mounted in the interior volume of the housing, intermediate the front and rear walls of the housing, the baffle plate having an edge in spaced relation to the side wall to form an annular flow passage therebetween and the baffle plate having at least one of the respective fluids directed thereagainst upon introduction to the interior volume of the housing, for distribution thereof in the interior volume of the housing. The baffled showerhead disperser is usefully employed to enable formation of CVD thin films of highly uniform composition and thickness.