Thermogravimetric evaluation of the suitability of precursors for MOCVD

Kunte, G. V.; Shivashankar, S. A.; Umarji, A.M.

doi:10.1088/0957-0233/19/2/025704

Cited by 78 publications

(99 citation statements)

References 10 publications

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“…Thermally stable compounds also leave a very low final residual mass indicative of evaporation without decomposition to non‐volatile by‐products. The vapor pressure of a compound can be calculated from TGA data using a previously developed method (Figures S38–S45) . The temperature at which a compound achieves a vapor pressure of 1 Torr (i.e., its 1 Torr temperature, T V ) may be used as a benchmark for comparison since commercial ALD reactors typically operate close to this pressure.…”

Section: Resultsmentioning

confidence: 99%

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Controlling the Thermal Stability and Volatility of Organogold(I) Compounds for Vapor Deposition with Complementary Ligand Design

et al. 2019

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Atomic layer deposition (ALD) of gold is being studied by multiple research groups, but to date no process using non‐energetic co‐reactants has been demonstrated. In order to access milder co‐reactants, precursors with higher thermal stability are required. We set out to uncover how structure and bonding affect the stability and volatility of a family of twelve organogold(I) compounds using a combination of techniques: X‐ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and density functional theory (DFT). Small, unsubstituted phosphonium ylide ligands bind more strongly to Au(I) than their silyl‐substituted analogues, but the utility of both these ligands suffers due to their poor volatility and substantial thermal decomposition. Pentafluorophenyl (C6F5) is introduced as a new, very electronegative ligand for gold vapor deposition precursors, and it was found that the disadvantage to volatility due to π‐stacking and other intermolecular interactions in the solid state was overshadowed by dramatic improvements to kinetic and thermodynamic stability. We introduce a new figure of merit to compare and rank the suitability of these and other complexes as precursors for vapor deposition. Finally, DFT calculations on four compounds that have high figures of merit show a linear correlation between the gold‐coordinative ligand bond dissociation energies and the observed decomposition temperatures, highlighting and justifying this design strategy.

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Section: Resultsmentioning

confidence: 99%

“…Both TGA and DSC temperature ramp rates were 10.0 °C/min. Langmuir vapor pressure equations were derived from TGA data using a previously reported method with Cu(tmhd) 2 as the calibrant , …”

Section: Methodsmentioning

confidence: 99%

Controlling the Thermal Stability and Volatility of Organogold(I) Compounds for Vapor Deposition with Complementary Ligand Design

et al. 2019

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“…Since we are interested in these compounds as volatile precursors, we determined the temperature that produced sufficient volatility (1 Torr) using a stepped isothermal TGA. 49,50 This method utilizes the known vapour pressure of Cu(tmhd) 2 and comparison of its volatility to that of 1 or 2. 51 Single-source, hot-walled CVD experiments were performed using 1 and 2 over a substrate temperature range of 150 -500 ºC using Si [100] substrates on a home-built apparatus.…”

Section: Resultsmentioning

confidence: 99%

Surfactant Directed Growth of Gold Metal Nanoplates by Chemical Vapor Deposition

et al. 2015

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Surface-supported, low-dimensional gold nanostructures are of interest for plasmonic applications. Low dimensional nanostructures are readily accessible by solution-phase growth, where shape control through the addition of growthdirecting surfactants is well established. Yet, shape control in chemical vapour deposition (CVD) has not been well explored, and metallic gold films are typically limited to nanoparticulate or thin film morphologies. This article describes the self-seeded growth of high aspect ratio gold plates and wires by CVD. A directed growth mechanism is proposed, where growth is directed by the coordinating N-heterocyclic carbene (NHC) and phosphine ligands originating from the thermal decomposition of the two gas-phase precursors, [Au(HMDS)(NHC)] (HMDS = hexamethyldisilazide, NHC = 1,3-diisopropyl-imidazolidin-2-ylidene) and [Au(HMDS)(PMe 3 )]. These ligands acted as transient surfactants for plate growth between 370 and 460°C and at high precursor flux. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) evidence indicates that hydroxyl terminated substrate surfaces are passivated with trimethylsilyl (TMS) moieties originating from the HMDS ligand in both precursors, which promoted island type growth and directed precursor decomposition to occur on gold surfaces. Secondary nucleation is observed on all gold structures, and is a crucial component to gas-phase surfactant-mediated CVD growth. This work identifies the potential to use precursor-bound coordinative ligands or gas-phase surfactants to direct growth of metal nanocrystals by CVD.

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“…This experiment can be used to relate the mass lost as vapour to the Langmuir equation, to establish vapour pressure as a function of temperature. 31 Compound 1 was shown to be more volatile at lower temperatures, and to have 1 Torr of vapour pressure at 131 °C (using benzoic acid as a standard). Compound 2 had a slightly lower volatility, and gave 1 Torr of vapour pressure at 139 °C.…”

Section: Resultsmentioning

confidence: 99%

Deposition of Copper by Plasma-Enhanced Atomic Layer Deposition Using a Novel N-Heterocyclic Carbene Precursor

et al. 2013

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Access to the full text of the published version may require a subscription. Rights AbstractTwo novel N-heterocyclic carbene (NHC)-containing copper(I) amides are reported as atomic layer deposition (ALD) precursors. 1,3-diisopropyl-imidazolin-2-ylidene copper hexamethyldisilazide (1) and 4,5-dimethyl-1,3-diisopropyl-imidazol-2-ylidene copper hexamethyldisilazide (2) were synthesized and structurally characterized. The thermal behaviour of both compounds was studied by thermogravimetric analysis (TGA), and they were both found to be reasonably volatile compounds. Compound 1 had no residual mass in the TGA and showed long-term stability at temperatures as high as 130 °C, while 2 had a residual mass of 7.4 %. Copper metal with good resistivity was deposited using 1 by plasma-enhanced atomic layer deposition. The precursor demonstrated self-limiting behaviour indicative of ALD, and gave a growth rate of 0.2 Å/cycle. Compound 2 was unsuccessful as an ALD precursor under similar conditions. Density functional theory calculations showed that both compounds adsorb dissociatively onto a growing copper film as long as there is some atomic roughness, via cleavage of the Cu-carbene bond.

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Thermogravimetric evaluation of the suitability of precursors for MOCVD

Cited by 78 publications

References 10 publications

Controlling the Thermal Stability and Volatility of Organogold(I) Compounds for Vapor Deposition with Complementary Ligand Design

Controlling the Thermal Stability and Volatility of Organogold(I) Compounds for Vapor Deposition with Complementary Ligand Design

Surfactant Directed Growth of Gold Metal Nanoplates by Chemical Vapor Deposition

Deposition of Copper by Plasma-Enhanced Atomic Layer Deposition Using a Novel N-Heterocyclic Carbene Precursor

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