a process chamber containing a platen for supporting a substrate; and

a plasma source disposed adjacent the process chamber and adapted to produce free radicals in a plasma chamber, the plasma chamber having an aperture associated therewith for allowing a beam of the free radicals to exit the plasma chamber, wherein the aperture is defined by a radially-elongated nozzle extending directly from the plasma chamber away from the plasma chamber and having a depth in a range of 7 millimeters to 20 millimeters for collimating the beam of free radicals exiting the plasma chamber, wherein at least a portion of the nozzle is located entirely outside of the plasma chamber, and wherein the nozzle is separate from, is attached to, and extends at least partially into, a sidewall of the plasma chamber;

wherein the process chamber is maintained at a first pressure and the plasma chamber is maintained at a second pressure greater than the first pressure for driving the free radicals from the plasma chamber into the process chamber and onto the substrate;

wherein an entirety of the plasma chamber, including the nozzle, is rotatable for directing the beam toward the platen at an oblique angle relative to a surface of the platen.