Short-chain aminosilanes, namely, bis(N,Ndimethylamino)dimethylsilane (DMADMS) and (N,Ndimethylamino)trimethylsilane (DMATMS), have been used as Si precursors for atomic layer deposition (ALD) of SiO 2 . In this work, the DMADMS and DMATMS Si precursors are utilized as inhibitors for area-selective ALD (AS-ALD). The inhibitors selectively adsorb on a SiO 2 surface but not on H− Si, so that SiO 2 becomes selectively deactivated toward subsequent ALD. The deactivation of the SiO 2 surface by the inhibitors was investigated using various experimental and theoretical methods, including surface potential measurements, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy. Better inhibition was observed for ALD of Ru and Pt than for ALD of Al 2 O 3 and HfO 2 . Through quantum mechanical and stochastic simulations, the difference in the blocking ability for noble metal and metal oxide ALD by the aminosilane inhibitors could be attributed to the inherently partial surface coverage by the inhibitors at their saturation and the reactivity of the subsequent ALD precursors. As silane inhibitors can be easily integrated with vacuum-based processes to facilitate high volume manufacturing of upcoming electronic devices, the current study provides a potential approach for the utilization of AS-ALD in pattern fabrication inside 3D nanostructures.

Area-selective atomic layer deposition (AS-ALD) is a promising bottom-up patterning approach for fabricating conformal thin films. One of the current challenges with respect to AS-ALD is the deficiency of the surface inhibitor used for fabricating nanoscale three-dimensional structures. In this study, a vapor-deliverable small inhibitor called ethanethiol (ET) that thermally adsorbs on surfaces was used for the AS-ALD of Al2O3. The inhibitor selectively adsorbed on Co and Cu substrates but not on the SiO2 substrate, allowing for the selective deactivation of Co and Cu substrates in Al2O3 ALD. The use of dimethylaluminum isopropoxide (DMAI) as the Al precursor resulted in better inhibition than the use of trimethylaluminum (TMA). Various experimental and theoretical methods, including water contact angle measurements, spectroscopic ellipsometry, X-ray photoelectron spectroscopy, density functional theory calculations, and Monte Carlo simulations, were used to elucidate the process of AS-ALD using ET. Dimerization of the DMAI precursor is considered to be a governing factor for its high deposition selectivity, while the probability of this phenomenon is very low for the TMA precursor. The current study provides insight into the selectivity of AS-ALD from the perspective of the chemical reaction and an opportunity to improve selectivity via precursor selection.

Two counter reactants, H2O and O3, were individually employed, as well as in combination with consecutive exposure by H2O–O3 and O3–H2O. The film growth behaviors and properties differed when the sequence of exposure of the substrate to the reactants was varied.