Oxidation properties of silicon nitride thin films fabricated by double tubed coaxial line type microwave plasma chemical vapor deposition

Silicon nitride films have fabricated under different deposition conditions using a double tubed coaxial line type microwave plasma chemical vapor deposition system. The oxidation and annealing properties of the films have been analyzed using infrared absorption spectroscopy. It is shown that oxidation proceeds via (Si-H₂)_n bonds in the voids. During the process, hydrogen atoms are released. The N-H bonds which form the remainder in the bulk are not affected by oxidation. Based on this finding, films which have a large concentration of N-H bonds and a lower concentration of Si-H bonds show greater resistance to oxidation. Under adequate conditions, the stoichiometric oxidation-resistant silicon nitride films can be fabricated outside the discharge plasma even at room temperature.