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Selective Gas-Phase Functionalization of SiO2 and SiNx Surfaces with Hydrocarbons
Langmuir ( IF 3.7 ) Pub Date : 2021-03-17 , DOI: 10.1021/acs.langmuir.1c00212 Ryan J. Gasvoda 1 , Wanxing Xu 1 , Zhonghao Zhang 2 , Scott Wang 2 , Eric A. Hudson 2 , Sumit Agarwal 1
Langmuir ( IF 3.7 ) Pub Date : 2021-03-17 , DOI: 10.1021/acs.langmuir.1c00212 Ryan J. Gasvoda 1 , Wanxing Xu 1 , Zhonghao Zhang 2 , Scott Wang 2 , Eric A. Hudson 2 , Sumit Agarwal 1
Affiliation
Selective functionalization of dielectric surfaces is required for area-selective atomic layer deposition and etching. We have identified precursors for the selective gas-phase functionalization of plasma-deposited SiO2 and SiNx surfaces with hydrocarbons. The corresponding reaction mechanism of the precursor molecules with the two surfaces was studied using in situ surface infrared spectroscopy. We show that at a substrate temperature of 70 °C, cyclic azasilanes preferentially react with an −OH-terminated SiO2 surface over a −NHx-terminated SiNx surface with an attachment selectivity of ∼5.4, which is limited by the partial oxidation of the SiNx surface. The cyclic azasilane undergoes a ring-opening reaction where the Si–N bond cleaves upon the reaction with surface −OH groups forming a Si–O–Si linkage. After ring opening, the backbone of the grafted hydrocarbon is terminated with a secondary amine, −NHCH3, which can react with water to form an −OH-terminated surface and release CH3NH2 as the product. The surface coverage of the grafted cyclic azasilane is calculated as ∼3.3 × 1014 cm–2, assuming that each reacted −OH group contributes to one hydrocarbon linkage. For selective attachment to SiNx over SiO2 surfaces, we determined the reaction selectivity of aldehydes. We demonstrate that aldehydes selectively attach to SiNx over SiO2 surfaces, and for the specific branched aliphatic aldehyde used in this work, almost no reaction was detected with the SiO2 surface. A fraction of the aldehyde molecules reacts with surface −NH2 groups to form an imine (Si–N═C) surface linker with H2O released as the byproduct. The other fraction of the aldehydes also reacts with surface −NH2 groups but do not undergo the water-elimination step and remains attached to the surface as an aminoalcohol (Si–NH–COH−). The surface coverage of the grafted aldehyde is calculated as ∼9.8 × 1014 cm–2 using a known infrared absorbance cross-section for the −C(CH3)3 groups.
中文翻译:
烃对SiO 2和SiN x表面的选择性气相功能化
电介质表面的选择性功能化对于区域选择性原子层沉积和蚀刻是必需的。我们已经确定了碳氢化合物对等离子体沉积的SiO 2和SiN x表面进行选择性气相功能化的前体。使用原位表面红外光谱研究了前体分子在两个表面上的相应反应机理。我们表明,在70°C的底物温度下,环状氮杂硅烷优先于-NH x终止的SiN x表面与-OH终止的SiO 2表面反应,其连接选择性为〜5.4,这受部分氧化的限制。 SiN x的表面。环状氮杂硅烷会发生开环反应,该反应中的Si–N键与表面的-OH基团反应形成Si–O–Si键而断裂。开环后,接枝烃的骨架被仲胺-NHCH 3终止,仲胺可与水反应形成-OH端基表面并释放出CH 3 NH 2产物。假设每个已反应的-OH基团都有助于一个烃键,则接枝的环状氮杂硅烷的表面覆盖率约为3.3×10 14 cm -2。用于选择性地附着在SiO 2上的SiN x上在表面上,我们确定了醛的反应选择性。我们证明了醛选择性地附着在SiO 2表面上的SiN x上,对于这项工作中使用的特定支链脂族醛,几乎没有检测到与SiO 2表面的反应。一部分醛分子与表面-NH 2基反应形成亚胺(Si–N═C)表面连接物,并释放出H 2 O作为副产物。醛的其他部分也与表面-NH 2基团反应,但不进行除水步骤,并以氨基醇(Si–NH–COH–)的形式附着在表面上。接枝醛的表面覆盖率经计算约为9.8×10 14cm –2使用-C(CH 3)3基团的已知红外吸收截面。
更新日期:2021-04-06
中文翻译:
烃对SiO 2和SiN x表面的选择性气相功能化
电介质表面的选择性功能化对于区域选择性原子层沉积和蚀刻是必需的。我们已经确定了碳氢化合物对等离子体沉积的SiO 2和SiN x表面进行选择性气相功能化的前体。使用原位表面红外光谱研究了前体分子在两个表面上的相应反应机理。我们表明,在70°C的底物温度下,环状氮杂硅烷优先于-NH x终止的SiN x表面与-OH终止的SiO 2表面反应,其连接选择性为〜5.4,这受部分氧化的限制。 SiN x的表面。环状氮杂硅烷会发生开环反应,该反应中的Si–N键与表面的-OH基团反应形成Si–O–Si键而断裂。开环后,接枝烃的骨架被仲胺-NHCH 3终止,仲胺可与水反应形成-OH端基表面并释放出CH 3 NH 2产物。假设每个已反应的-OH基团都有助于一个烃键,则接枝的环状氮杂硅烷的表面覆盖率约为3.3×10 14 cm -2。用于选择性地附着在SiO 2上的SiN x上在表面上,我们确定了醛的反应选择性。我们证明了醛选择性地附着在SiO 2表面上的SiN x上,对于这项工作中使用的特定支链脂族醛,几乎没有检测到与SiO 2表面的反应。一部分醛分子与表面-NH 2基反应形成亚胺(Si–N═C)表面连接物,并释放出H 2 O作为副产物。醛的其他部分也与表面-NH 2基团反应,但不进行除水步骤,并以氨基醇(Si–NH–COH–)的形式附着在表面上。接枝醛的表面覆盖率经计算约为9.8×10 14cm –2使用-C(CH 3)3基团的已知红外吸收截面。