Reduction of carbon impurity in silicon nitride films deposited from metalorganic source

Silicon nitride (SiNx) film has been deposited at a substrate temperature in the range of 200–800°C by a new radical-beam deposition technique. In the new technique, hexamethyldisilazane is decomposed not in plasma directly, but in a reaction with atomic nitrogen, in order to reduce carbon concentration into the film. The carbon concentration of the film is estimated to be of the order of 1019 cm-3 at most, based on secondary ion mass spectroscopy. The resistivity and the dielectric constant of the film are evaluated to be ~1013 Ωcm at 3 MV/cm and 5.7 at 300 kHz, respectively, which makes the film quality comparable to that of SiNx films deposited by plasma chemical vapor deposition.