Solution Layer Deposition: A Technique for the Growth of Ultra‐Pure Manganese Oxides on Silica at Room Temperature

Abstract

With the ever increasing miniaturization in microelectronic devices, new deposition techniques are required to form high-purity metal oxide layers. Herein, we report a liquid route to specifically produce thin and conformal amorphous manganese oxide layers on silicon substrate, which can be transformed into a manganese silicate layer. The undesired insertion of carbon into the functional layers is avoided through a solution metal-organic chemistry approach named Solution Layer Deposition (SLD). The growth of a pure manganese oxide film by SLD takes place through the decoordination of ligands from a metal-organic complex in mild conditions, and coordination of the resulting metal atoms on a silica surface. The mechanism of this chemical liquid route has been elucidated by solid-state (29) Si MAS NMR, XPS, SIMS, and HRTEM.

A Novel Method for the Metallization of 3D Silicon Induced by Metastable Copper Nanoparticles

“…The MnSiO 3 barrier layer was deposited by a process developed in our team. 17 After Cu deposition, annealing was performed at 300°C during 3 h under a H 2 flow to stabilize the copper layer. After these steps, the substrate was used as the working electrode for the electrodeposition of thick copper layer.…”

“…Beyond the interest of this process for Cu layer deposition on silicon substrates comprising a copper diffusion barrier 17 (MnSiO 3 , see Experimental and Materials section), it has been employed on 3D silicon substrates presenting high aspect ratio structures like vias (depth and entry dimensions: 175−50 μm and 100−10 μm, aspect ratios of 3.5 and 10 respectively) or trenches (25−0.8 μm, aspect ratio of 31). Figure 8 presents cross section views of vias and trenches observed after ca.…”

“…The deposition of Cu films was performed on a SiO 2 /Si substrate covered with a thin MnSiO 3 barrier layer. The MnSiO 3 barrier layer was deposited by a process developed in our team . After Cu deposition, annealing was performed at 300 °C during 3 h under a H 2 flow to stabilize the copper layer.…”

Redox Layer Deposition of Thin Films of MnO2 on Nanostructured Substrates from Aqueous Solutions

“…While Cure et al recently showed the growth of manganese oxides at room temperature and partially in a liquid phase, this approach still required a dedicated synthesis of the metalorganic precursor (MnAmd2), the processing in anhydrous toluene, in neutral gas environment and utilization of oxygen plasma. 19 Similarly, some solution-based ALD processes were previously described for other oxides, such as TiO2 or MgO, but they were always limited by the need of controlled, neutral gas environment and partially anhydrous conditions. 20,21 In our approach, we avoided the challenges posed by the classical ALD processes by using aqueous solutions of common KMnO4 as the manganese precursor and a surface-adsorbing alcohol as the permanganate reducer (Figure 1).…”

“…Second, because the as-grown MnO 2 is also a catalyst for ozone decomposition, ALD of MnO 2 on nanostructured substrates with large surface area may be unfeasible, as suggested by the reports on this ALD process. ,, Furthermore, both the thermal- and plasma-ALD processes are vacuum techniques performed at elevated temperatures, requiring costly and reactive metal–organic precursors and a sophisticated, thermally isolated vacuum equipmentimplying a high processing cost. While Cure et al recently showed the growth of manganese oxides at room temperature and partially in a liquid phase, this approach still required a dedicated synthesis of the metal–organic precursor (MnAmd 2 ), the processing in anhydrous toluene, in neutral gas environment, and utilization of oxygen plasma . Similarly, some solution-based ALD processes were previously described for other oxides, such as TiO 2 or MgO, but they were always limited by the need of controlled, neutral gas environment, and partially anhydrous conditions. , …”