Surface reactions of aminosilane precursors during N2 plasma‐assisted atomic layer deposition of SiNx

The surface reactions during atomic layer deposition (ALD) of SiNx were studied using in situ attenuated total reflection Fourier transform infrared spectroscopy. Specifically, di(sec‐butylamino)silane (DSBAS) and bis(diethylamino)silane (BDEAS) were used as the silicon precursors with N 2 plasma as the nitrogen source for SiN x ALD over a temperature range of 225–375°C. The infrared spectra recorded during each ALD half‐cycle provide unambiguous experimental evidence that surface secondary amines (>NH) are the primary reactive sites for chemisorption of DSBAS and BDEAS on a SiN x surface that was exposed to an N 2 plasma. Based on these observations, we predict that most aminosilane precursors will primarily react with surface >NH groups: This observation is contrary to most atomistic‐level simulations for this reaction that predict a high activation energy barrier. Infrared spectra recorded during each atomic layer deposition half‐cycle provide unambiguous experimental evidence that surface secondary amines (>NH) are the primary reactive sites for chemisorption of DSBAS and BDEAS on a SiNx surface that was exposed to an N 2 plasma. Based on these observations, we predict that most aminosilane precursors will primarily react with surface >NH groups: This observation is contrary to most atomistic‐level simulations for this reaction that predict a high activation energy barrier.