Atomic layer deposition of ternary ruthenates by combining metalorganic precursors with RuO₄ as the co-reactant

Abstract

ALD of aluminum ruthenate and platinum ruthenate are achieved by combining a metalorganic precursor with RuO4 as oxidizing agent and Ru source.

Shuffling Atomic Layer Deposition Gas Sequences to Modulate Bimetallic Thin Films and Nanoparticle Properties

“…Only in the latter case, growth is observed. This phenomenon is different from the Al- and Pt-ruthenates (Al x Ru y O z or Pt x Ru y O z ) grown in Minjauw et al, where [TMA/RuO 4 ] and [MeCpPtMe 3 /RuO 4 ] ALD processes yield Al- or Pt-ruthenates without reducing agents. This shows that Pd­(hfac) 2 requires a fully reduced metal surface with H terminal groups to allow for reaction and thus deposition.…”

“…Figure a schematically shows the process sequences of the (top) monometallic Pd [Pd­(hfac) 2 /H 2 *], (middle) monometallic Ru [RuO 4 /H 2 *], and (bottom) bimetallic Pd–Ru ALD processes [Pd­(hfac) 2 /RuO 4 /H 2 *]. In the latter process, RuO 4 presents as a multiconstituent co-reactant since it fulfills a dual function as a co-reactant to combust the hfac ligands after Pd­(hfac) 2 exposure but also as a Ru source . The final H 2 * plasma pulse of the bimetallic process also fulfills two functions: (i) reduction of the oxidized surface to obtain bimetallic instead of oxide films, (ii) H-termination of the thin film surface as a “primer” for subsequent Pd deposition, thus allowing continuous Pd-on-Ru growth.…”

“…A variety of ternary ALD “strategies” have been developed, which allow A m B n C o (A m B n ) deposition, including (i) co-dosing of two metal precursors in one pulse, (ii) multicomponent precursors containing two metals, and (iii) multiconstituent co-reactants. , The latter is of particular interest (Figure , right-bottom) since the co-reactant has a dual function: it does not only remove the ligands of precursor A but also introduces a secondary metal source, thus simultaneously forming metal precursor B. Recently, Minjauw et al developed ternary Al m Ru n O o and Pt m Ru n O o oxides by combining TMA (trimethyl aluminum) or MeCpPtMe 3 precursors, on the one hand, as metal source A and RuO 4 , on the other hand, as precursor B and co-reactant. Therein, RuO 4 is not a classic metal–organic precursor but rather a metal–oxide monomer, which employs its O-ligands to combust the remaining organic ligand (fragments) of the TMA or MeCpPtMe 3 precursors.…”

“…It is clear that (i) multiple functions can be built into a single ALD process, e.g., metal source, ligand exchange agent, reductant, and etching step (see Vos et al) but also that (ii) single pulses within the ALD processhere termed “components”can fulfill multiple functions, e.g., metal source as well as ligand exchange agent for multiconstituent co-reactant (see Minjauw et al). Inspired by the diversity of these functionalities and the ability of ALD to implement them flexibly, herein, we freely sequence different functionalities to construct the ALD process.…”

Atomic Layer Deposition of the Conductive Delafossite PtCoO2

“…[ 42 ] We would like to mention that Minjauw et al. [ 43 ] reported ternary ALD processes for ruthenates during the preparation time for this article. This article focused on the low‐temperature growth chemistry using RuO 4 with trimethyl aluminum and trimethyl‐Pt‐methylcyclopentadienyl (Me 3 Pt(CpMe)) but did not report the formation of a crystalline ternary phase.…”