Synthesis, characterization, and thermal properties of volatile 1,4-dialkyl-5-silatetrazolines: nitrogen-rich silicon heterocycles as possible CVD precursors for silicon nitride

Abstract

We describe the synthesis, thermal properties, and volatilities of three 1,4-dialkyl-5-silatetrazolines of the form (L)Si(N₄R₂), where R = Et (2), ⁱPr (3), or ^tBu (4) and L is the 1,4-diazabutenediyl chelate ^tBuNCHCHN^tBu. The compounds were characterized by NMR and IR spectroscopy and X-ray crystallography. Volatility studies show that compound 2, the 1,4-diethyl-5-silatetrazoline compound, is the most volatile of the three new compounds, exhibiting a 1 Torr vapor pressure at 95 °C and subliming at 65 °C and 5 mTorr. These compounds are of interest as possible low temperature CVD precursors for the growth of silicon nitride (SiN_x) thin films.