High‐rate, low‐temperature deposition of multifunctional nano‐crystalline silicon nitride films

Abstract

The solid phase compositions and dielectric properties of silicon nitride (SiNx) films prepared using the plasma enhanced chemical vapor deposition (PECVD) technique at a low temperature (200°C) were studied. Controlling the source gas mixing ratio, R = [N2]/[SiH4], and the plasma power successfully produced both silicon‐rich and nitrogen‐rich compositions in the final films. The composition parameter, X, varied from 0.83 to 1.62. Depending on the film composition, the dielectric properties of the SiNx films also varied substantially. Silicon‐rich silicon nitride (SRSN) films were obtained at a low plasma power and a low R. The photoluminescence (PL) spectra of these films revealed the existence of nano‐sized silicon particles even in the absence of a post‐annealing process. Nitrogen‐rich silicon nitride (NRSN) films were obtained at a high plasma power and a high R. These films showed a fairly high dielectric constant (κ = 7.1) and a suppressed hysteresis window in their capacitance‐voltage (C‐V) characteristics.