Atomic Layer Deposition of Silicon Dioxide Using Aminosilanes Di-sec-butylaminosilane and Bis(tert-butylamino)silane with Ozone

In situ Fourier transform infrared (FTIR) spectroscopy is used to investigate silicon dioxide deposition on OH-terminated oxidized Si(100) surfaces using two aminosilanes, di-sec-butylaminosilane (DSBAS) and bis(tert-butylamino)silane (BTBAS), with ozone as the coreactant. Both DSBAS and BTBAS readily react at 100 °C with surface −OH groups (loss at 3745 cm–1) with formation of Si–O–SiH3 and Si–O–SiH2–(NHtBu), respectively, through elimination of secondary and primary amines. The (O−)SiH3 structure is characterized by a strong Si–O–Si band at 1140 cm–1, and sharp (O−)SiH3 stretch (2192 cm–1) and deformation (983 cm–1) bands. SiH3 remains stable up to 400 °C, at which point rearrangement into bidentate ((O−)2SiH2) and then tridentate ((O−)3SiH) bonding takes place through condensation reaction with neighboring OH or O groups. In contrast, the O–SiH2–(NHtBu) structure obtained from BTBAS exposure at 100 °C loses its NHtBu group at ∼350 °C, leading to a bidentate bonding ((O−)2SiH2) that remains stable up to...