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4245807 
Journal Article 
Atomic Layer Deposition of Silicon Dioxide Using Aminosilanes Di-sec-butylaminosilane and Bis(tert-butylamino)silane with Ozone 
Pena, LF; Nanayakkara, CE; Mallikarjunan, A; Chandra, H; Xiao, M; Lei, X; Pearlstein, RM; Derecskei-Kovacs, A; Chabal, YJ 
2016 
Yes 
Journal of Physical Chemistry C
ISSN: 1932-7447
EISSN: 1932-7455 
120 
20 
10927-10935 
WOS:000376840900020 
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 degrees C with surface -OH groups (loss at 3745 cm(-1)) with formation of Si-O-SiH3 and Si-O-SiH2-((NHBu)-Bu-t), 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 degrees C, at which point rearrangement into bidentate ((O-)(2)SiH2) and then tridentate ((O-)(3)SiH) bonding takes place through condensation reaction with neighboring OH or O groups. In contrast, the O-SiH2-((NHBu)-Bu-t) structure obtained from BTBAS exposure at 100 degrees C loses its (NHBu)-Bu-t group at similar to 350 degrees C, leading to a bidentate bonding ((O-)(2)SiH2) that remains stable up to 500 degrees C. In both cases, the transformation to bidentate and tridentate bonding depends on the initial OH concentration. The degree of ligand exchange during atomic layer deposition (ALD) with ozone also depends on the ozone flux. For a high enough flux (>= 300 sccm, P similar to 7.5 Torr), the ligand exchange is essentially complete, with the ozone pulse reacting with Si-H-x [loss of vibrational bands at 2192 and 983 cm(-1) for DSBAS, and at 2972, 2185, and 924 cm(-1) for BTBAS] and forming surface Si-O-H (3745 cm(-1)). The initial Si-O-Si band at 1140 cm(-1) broadens upon ozone exposure, consistent with the formation of a Si-O-Si network that extends the existing SiO2 substrate. In steady state, the ALD process is characterized by reaction of SiHx by ozone with the formation of OH, thus sustaining the ALD process, with densification of stoichiometric silicon oxide [transverse optical (TO) and longitudinal optical (LO) phonon modes at 1053 and 1226 cm(-1)].