Dense Structure of SiNx Films Fabricated by Radical Beam Deposition Method Using Hexamethyldisilazane

The mass density was evaluated by Rutherford backscattering spectroscopy for silicon nitride (SiNx) films with considerably low carbon concentration deposited from hexamethyldisilazane by the radical beam deposition method. The mass density of the film deposited at a low substrate temperature (room temperature ~ 400°C) was comparable to those of conventional SiNx films deposited from SiH4. This indicates a compatibilty of the film in this work with conventional films. For the films deposited at a substrate temperature above 400°C, H and excess N were eliminated from the film, and the mass density was evaluated to be 3.2 g/cm3, which is comparable to that of Si3N4 formed by the sintering method.