LAUSR

Abstract High-quality silicon nitride (SiNx) thin films were grown by remote-plasma-activated pulsed chemical vapor deposition (P-CVD) from the source precursor 1,3,5-tri(isopropyl)cyclotrisilazane (TICZ, C9H27N3Si3) and remote ammonia (NH3) plasma on silicon oxide (SiO2) substrates within an optimized substrate temperature window ranging from 200 to 350 °C. TICZ was selected because of its chemical stability, non-pyrophoric nature, good vapor pressure (~127 Pa at 70 °C), and its chemical structure that incorporates alkyl groups with three C atoms on each N atom, which provides a clean elimination mechanism for low temperature SiNx deposition. P-CVD consisted of a four-step process: TICZ pulse with no plasma, N2 purge, NH3 plasma pulse, and N2 purge. The as-deposited films were analyzed using spectroscopic ellipsometry and x-ray photoelectron spectroscopy (XPS). Wet etch rates were determined using a standard solution consisting of 0.5% hydrofluoric acid in deionized water. XPS analysis revealed a Si:N ratio of ~1:1 within the entire substrate temperature range and validated the formation of the SiNx phase. In situ, real-time ellipsometry measurements confirmed that SiNx growth exhibited a non-self-limiting P-CVD behavior. They also yielded an as-grown SiNx average refractive index of ~1.8 for the films grown at substrate temperatures above 200 °C.