An apparatus and methods for an upgraded CVD system that provides a plasma for efficiently cleaning a chamber, according to a specific embodiment. Etching or depositing a layer onto a substrate also may be achieved using the upgraded CVD system of the present invention. In a specific embodiment, the present invention provides an easily removable, conveniently handled, and relatively inexpensive microwave plasma source as a retrofit for or a removable addition to existing CVD apparatus. In a preferred embodiment, the remote microwave plasma source efficiently provides a plasma without need for liquid-cooling the plasma applicator tube. In another embodiment, the present invention provides an improved CVD apparatus or retrofit of existing CVD apparatus capable of producing a plasma with the ability to efficiently clean the chamber when needed.