Remote plasma atomic layer deposition of silicon nitride with bis(dimethylaminomethyl-silyl)trimethylsilyl amine and N-2 plasma for gate spacer

Abstract

The silicon nitride (SiNx) atomic layer deposition with bis(dimethylaminomethylsilyl)trimethylsilyl amine precursor and N-2 remote plasma was investigated. The process window ranged from 250 to 400 degrees C, and the growth rate was about 0.38 +/- 0.02 angstrom/cycle. The physical, chemical, and electrical characteristics of the SiNx thin films were examined as a function of deposition temperature and plasma power. Based on the results of spectroscopic ellipsometry and x-ray photoelectron spectroscopy, the growth rate and state of binding energy showed little difference depending on the plasma power. The better film properties such as leakage current density and etch resistance were obtained at higher deposition temperatures and higher plasma power. High wet etch resistance (wet etch rate of similar to 2 nm/min) and low leakage current density (similar to 10(-8) A/cm(2)) were obtained. The step coverage, examined by transmission electron microscopy, was about 80% on a trench with an aspect ratio of 4.5.