Reaction of Methylcyclopentadienyl Manganese Tricarbonyl on Silicon Oxide Surfaces: Implications for Thin Film Atomic Layer Depositions

Abstract

The thermal chemistry of methylcyclopentadienyl manganese tricarbonyl (MeCpMn(CO) 3 ) on silicon oxide surfaces was characterized by a combination of analytical techniques, including gas chromatography/mass spectrometry (GC−MS), temperature-programmed desorption (TPD), infrared absorption spectroscopy, and Xray photoelectron spectroscopy (XPS). The compound was found to be fairly stable, but to be able to dissociatively chemisorb on the surface via the loss of one or more carbonyl ligands followed by the oxidative addition of a surface silanol group. Further activation leads to the loss of the aromatic ligand, at temperatures above approximately 575 K. This takes place primarily via the addition of a hydrogen atom to the MeCp ligand to form methylcyclopentadiene, which is released to the gas phase, but a small competing channel starts at slightly lower temperatures that yields fulvene, and/or possibly benzene, after molecular rearrangement. The clean nature of the chemistry seen here for the methylcyclopentadienyl Mn complex makes it a good candidate as a precursor in the chemical deposition of metal thin films. However, the high stability and the high temperatures required for its decomposition do introduce some limitations.

Adsorption of Metallocenes on Silica

“…This way,atimeline for adsorption can be established ( Figure 5). Importantly,i nc ontrastt o1, 3 does not react with any silica surface in an inert atmosphere under mild conditions, [19] which is also proveni nt his work using IR spectroscopy (see below). As the gap between the two materials widens, the adsorptions lows down and the silica gel pieces tarts to assume ayellow color also from the other sides of the piece.…”

“…Both (a) and (b) explain the presence of two different Cp ring signals and their differentl inewidths. [19] IR spectroscopy often provides important information regardingt he structure and integrity of complexes containing CO groups. Regarding the higher maximal loading of 3a with 2.762 mmol g À1 as compared to 1a and 4a with 2.090 mmol g À1 (Table 1) renders explanation (b) more likely.…”

“…Furthermore, the approximate 1:1i ntensity ratio of the signals is accounted for in (a) and (b). The IR spectra of (i)p olycrystalline cymantrene, [19,24] 3 adsorbed (ii)w ith maximal surface coverage, (iii)i nasub-monolayer,a sw ell as (iv) 3 dissolved in toluene have been recorded. The fact that double the loading of 1a is not achieved by 3a can be explained by the larger footprint of the dimers of 3, which exhibit ak ink in the structure.…”

Incomplete elimination of precursor ligands during atomic layer deposition of zinc-oxide, tin-oxide, and zinc-tin-oxide

“…These so-called "difference spectra" show the changes of the surface upon exposure to the precursor or co-reactant. 23,[28][29][30][31] However, information of persisting ligands and other nucleation effects is lost when representing the data in this way, especially when FTIR spectra are only recorded after conditioning the reactor/coating the powder. This will be illustrated with the dataset for SnO 2 ALD shown in Fig.…”

Coating of Vertically Aligned Carbon Nanotubes by a Novel Manganese Oxide Atomic Layer Deposition Process for Binder‐Free Hybrid Capacitors

“…In addition to the above mentioned and most commonly used manganese precursors, methylcyclopentadienyl manganese tricarbonyl (MeCpMn(I)(CO) 3 ) has been suggested as a promising precursor for the ALD of manganese containing films. This precursor presents sufficient volatility and thermal stability needed in ALD gas‐phase process . As a matter of fact, due to its volatility it was already applied for the Chemical Vapor Deposition (CVD) of Mn, MnO x , and MnSi x O y .…”