The effect of plasma power on the properties of low‐temperature silicon nitride deposited by RPALD for a gate spacer

Abstract

We investigated the effects of NH3 plasma power on characteristics of low‐temperature silicon nitride thin films for application of a gate spacer. SiNx thin film was deposited on a Si(100) substrate by remote plasma atomic layer deposition (RPALD) using trisilylamine (TSA) as a Si precursor and NH3 gas as a reactant. NH3 remote plasma was analyzed with optical emission spectroscopy (OES) and it largely consisted of NH and H. As the plasma power increased, more NH and H radicals were generated and a proportion of NH radicals in the plasma increased, which resulted in the slight increase of the high‐N content and low‐H content in SiNx thin film. The low‐H content with nearly stoichiometric SiNx thin films improve etch rate properties. The densities of RPALD SiNx thin film were 2.7 g cm−3 and almost the same regardless of plasma power. RPALD SiNx thin films showed a low leakage current density of 10−7 A cm−2 at 2 MV cm−1 and a breakdown voltage of approximately 8 MV cm−1.