U.S. Pat. No. 5,129,958 discloses a method for cleaning a CVD deposition chamber in a semiconductor wafer processing apparatus wherein fluorine residues in the chamber, left from a prior fluorine plasma cleaning step, are contacted with one or more reducing gases such as silane (SiH4), ammonia, hydrogen, phosphine (PH3), diborine (B2H6), and arsine (AsH3).