[3B01-11] Low-dimensional Material / Nanostructure / Nanomaterial (LD/NS/NM))

10:00 AM - 10:30 AM JST(1:00 AM - 1:30 AM UTC)

[3B05【招待講演】] In situ XPS observation of the adsorption and decomposition of amino silane precursors for SiO₂ ALD

*Kazuhiko Endo¹ (1. Insitute of Fluid Science, Tohoku University (Japan))

We investigated the initial adsorption states of tris(dimethylamino)silane (TDMASi), bis(diethylamino)silane (BDEASi), and di(isopropylamino)silane (DIPASi) for SiO₂ ALD using in situ x-ray photoelectron spectroscopy with vacuum transfer. After a 0.5 s precursor pulse without oxidation, the normalized Si 2p/O 1s saturation values were nearly identical for all three precursor. In contrast, N 1s and C 1s analyses revealed strong precursor-dependent ligand retention: TDMASi and BDEASi left substantial nitrogen- and carbon-containing species, whereas DIPASi showed no detectable N 1s signal and only a small C contribution. Deconvolution of the N 1s spectra indicated that the remaining nitrogen species after TDMASi and BDEASi dosing consisted mainly of N-C and N-Si, with a minor N-O component. These results demonstrate that precursor-dependent ligand removal and readsorption, rather than initial Si coverage, govern the first-half-cycle chemistry of aminosilane-based SiO₂ ALD.

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