Substrate Reactivity Effects in the Atomic Layer Deposition of Aluminum Oxide from Trimethylaluminum on Ruthenium

Abstract

A detailed study of the atomic layer deposition of Al 2 O 3 on Ru film surfaces by means of in situ photoelectron spectroscopy has been carried out. We discuss how the atomic layer deposition reaction between trimethylaluminum (TMA) and H 2 O is affected by the Ru substrate. We found that RuO 2 , when present on the substrate surface, participates in the reaction with TMA and the substrate reduces to Ru. The reduction of oxygencontaining substrates to Ru is solely due to the direct reaction of the Al precursor with the substrate through adsorption on active sites. The final Al 2 O 3 /Ru structures have an interface depleted from oxygen and show different band offsets depending on the initial chemistry.

Chemistry of active oxygen in RuOx and its influence on the atomic layer deposition of TiO2 films

“…To conrm this peculiarity, the physical and chemical properties of t4, t5, and t10 were examined in detail. 10 In contrast, the main contribution to the Ru 3d XPS peak was made by the peak with a 280.0 eV BE for the t10 case, suggesting that the lm was mainly Ru. Fig.…”

“…Many of the conventional lm growth processes that depended on the chemical vapour deposition (CVD) technique are now being replaced with the ALD processes, 6,7 although ALD was originally used mainly for thicker lm growth with high thickness accuracy over large glass surfaces for display applications. 10 Such ALD reaction routes can be provided by the efficient balance between the weak chemical bonding energy of Ru-O and the stronger reactivity between the ligand and the O atoms, which are extracted from the subsurface region of the growing lm. The surface of the substrate must provide the chemical adsorption sites, which would anchor the incoming metal or non-metal precursors via the ligand exchange reactions.…”

Room‐Temperature Atomic‐Layer‐Deposited Al2O3 Improves the Efficiency of Perovskite Solar Cells over Time

“…This fact is well knowni nt he ALD community and is attributed to the initial cleaningp rocess of the substrate surfaced uring the first few ALD cycles. [7,14] In particular, it is initially energetically more favourable forT MA to interact with the OH groups already located on the perovskite surface than with the OH groups of the H 2 Op recursor. This result is also consistentw ith the observed reduction of the OH groups on the perovskite surface, as shown in Figure S2.…”

Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films

“…Thin aluminum oxide (Al 2 O 3 ) layers deposited by atomic layer deposition (ALD) have been investigated for several applications like surface passivation or encapsulation in organic and inorganic photovoltaic devices [1–2], interfacial buffering for high-k dielectrics [3–4], organic memories [5], and nano-laminates [6] as well as work function modification [7], gas diffusion barrier [8] or corrosion protection [9]. Recently, there is a growing activity in covering photo-electrodes or electrodes by ultra-thin Al 2 O 3 ALD layers for electrochemical energy generation and storage systems [10] in order to enhance the efficiency and durability of such devices.…”