Hexakis(ethylamino)disilane (AHEAD) Si2(NHEt)6 is applicable for sub 90 nm Spacers and PMD liner. It has extra low deposition temperature capabilities for NiSi compatibility ( ~ 8A/min @450°C). Films deposited from this precursor have extremely low H content, higher wet etching resistance than SiN from any other precursors, good step coverage[568]
Extra low temperature silicon nitride growth (450-550°C) for cap & spacers was achieved with hexakis-ethylamidodisilane Si2(NHEt)6 (AHEADTM). It fulfils the requirements for such process: high deposition rate > 5 Ang/min @450°C, composrd only of Si, N, C, produces H < 5 1021 at/cm3, refractive index 1.98 < RI < 2.1, tunable stress < (+ or -) 2 Gpa, dielectric constant < 5, compatibility with NiSi, high conformality, low HF etch rate (< 10 Ǻ/min HF 0.5%) [AirLiquide]