Reductive Thermal Atomic Layer Deposition Process for Gold

Vihervaara, Anton; Hatanpää, Timo; Nieminen, Heta-Elisa; Mizohata, Kenichiro; Chundak, Mykhailo; Ritala, Mikko

doi:10.1021/acsmaterialsau.2c00075

Cited by 5 publications

(5 citation statements)

References 21 publications

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“…AuClPEt 3 has been used as an Au ALD precursor with a reported thermal stability up to 180 °C. 41 AuClPEt 3 is consistent with the reaction given in eq 2 and shown in the Au ALE mechanism in Figure 1. This reaction is thermochemically favorable, with a free energy change of ΔG = −53.8 kcal/mol at 150 °C.…”

Section: Chemistry Of Materialssupporting

confidence: 86%

“…The identification of the AuClPEt 3 etch product is consistent with previously observed Au compounds. AuClPEt 3 has been used as an Au ALD precursor with a reported thermal stability up to 180 °C . AuClPEt 3 is consistent with the reaction given in eq and shown in the Au ALE mechanism in Figure .…”

Section: Resultssupporting

confidence: 64%

“…40 A second thermal Au ALD process alternates between AuClPEt 3 as the Au-containing precursor and (Me 3 Ge) 2 DHP as a reducing agent. 41 Another work shows that a variety of volatile Au(I) precursors can be synthesized, with Au ALD demonstrated using alternating Au(N(SiMe 3 ) 2 )-(PEt 3 ) as the Au-containing precursor and BH 3 (NHMe 2 ) as a reducing agent. 42 In comparison to the few demonstrated Au ALD processes, there are no reported thermal ALE processes.…”

Section: Introductionmentioning

confidence: 99%

“…One thermal Au ALD process employs alternating Me 2 Au(S 2 CNEt 2 ) and O 3 reactants, where O 3 is used to combust the ligands of the Au precursor . A second thermal Au ALD process alternates between AuClPEt 3 as the Au-containing precursor and (Me 3 Ge) 2 DHP as a reducing agent . Another work shows that a variety of volatile Au(I) precursors can be synthesized, with Au ALD demonstrated using alternating Au(N(SiMe 3 ) 2 )(PEt 3 ) as the Au-containing precursor and BH 3 (NHMe 2 ) as a reducing agent …”

Section: Introductionmentioning

confidence: 99%

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Thermal Atomic Layer Etching of Gold Using Sulfuryl Chloride for Chlorination and Triethylphosphine for Ligand Addition

Partridge,

Murdzek,

Johnson

et al. 2024

Chem. Mater.

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Thermal atomic layer etching (ALE) of gold was achieved using sequential chlorination and ligand-addition reactions. This two-step process first chlorinated gold using sulfuryl chloride (SO 2 Cl 2 ) to form gold chloride. Subsequently, ligand addition to the gold chloride was performed using triethylphosphine (PEt 3 ) to yield a volatile gold etch product. Quartz crystal microbalance measurements on cubic crystalline gold films showed etching at temperatures from 75 to 175 °C. The most consistent etch rate was 0.44 ± 0.16 Å/ cycle at 150 °C. A mass increase was observed during each SO 2 Cl 2 exposure when forming the gold chloride. A mass loss was then monitored during each PEt 3 dose when ligand addition yielded a volatile etch product. In situ quadrupole mass spectrometry (QMS) studies on Au nanopowder at 150 °C showed the production of AuClPEt 3 as the dominant Au-containing etch product during PEt 3 exposures. Time-dependent QMS studies also observed the AuClPEt 3 + ion intensity peaking at the beginning of each PEt 3 exposure. The AuClPEt 3 + ion intensity then decreased as the PEt 3 + ion intensity remained constant. This behavior indicates a self-limiting ligandaddition reaction. X-ray photoelectron spectroscopy on these Au nanopowders showed evidence for AuClPEt 3 on the surface of the Au nanopowder when the final exposure was PEt 3 . Transmission electron microscopy analysis revealed that Au ALE did not roughen the crystalline Au nanoparticles. Powder X-ray diffraction measurements also showed narrower diffraction peaks after Au ALE on Au nanoparticles that were consistent with larger Au nanoparticles. This sintering effect may be caused by Au redistribution resulting from the disproportionation of the AuCl surface species. Using the same alternating exposures of SO 2 Cl 2 and PEt 3 , Cu and Ni nanopowders were also etched at 150 °C. Cu formed a volatile Cu 2 Cl 2 (PEt 3 ) 2 dimer during PEt 3 exposures at 150 °C. Likewise, Ni formed volatile NiCl 2 (PEt 3 ) 2 during PEt 3 exposures at 150 °C. Gibbs free energy changes from ab inito calculations support these etch product observations and offer a thermodynamic explanation for the formation of a copper dimer. These studies illustrate that sequential chlorination and ligand-addition reactions can provide a useful ALE pathway for gold and other metals.

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Section: Chemistry Of Materialssupporting

confidence: 86%

Section: Resultssupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal Atomic Layer Etching of Gold Using Sulfuryl Chloride for Chlorination and Triethylphosphine for Ligand Addition

Partridge,

Murdzek,

Johnson

et al. 2024

Chem. Mater.

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“…Finally, it is important to note that TGA is typically performed at atmospheric pressure, although low-pressure TGA has also been used to characterize CVD/ALD precursors. 33,46 Since most CVD/ALD reactors operate at low pressure, the volatility of potential precursors is often described by sublimation temperatures (and pressures).…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

Designing Volatile Molybdenum Compounds for Vapour-Phase Deposition

Land¹

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Atomic Layer Deposition of Molybdenum Carbide Thin Films

Kärkkäinen,

Popov,

Hatanpää

et al. 2024

Adv Materials Inter

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The development of deposition processes for metal carbide thin films is rapidly advancing, driven by their potential for applications including catalysis, batteries, and semiconductor devices. Within this landscape, atomic layer deposition (ALD) offers exceptional conformality, uniformity, and thickness control on spatially complex structures. This paper presents a comprehensive study on the thermal ALD of MoCx with MoCl5 and 1,4‐bis(trimethylgermyl)‐1,4‐dihydropyrazine [(Me3Ge)2DHP] as precursors, focusing on the functional properties and characterization of the films. The depositions are conducted at 200–300 °C and very smooth films with RMS Rq ≈0.3–0.6 nm on Si, TiN, and HfO2 substrates are obtained. The process has a high growth rate of 1.5 Å cycle−1 and the films appear to be continuous already after 5 cycles. The films are conductive even at thicknesses below 5 nm, and films above 18 nm exhibit superconductivity up to 4.4 K. In lieu of suitable references, Raman modes for molybdenum carbides and nitrides are calculated and X‐ray diffraction and X‐ray photoelectron spectroscopy are used for phase analysis.

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Reductive Thermal Atomic Layer Deposition Process for Gold

Cited by 5 publications

References 21 publications

Thermal Atomic Layer Etching of Gold Using Sulfuryl Chloride for Chlorination and Triethylphosphine for Ligand Addition

Thermal Atomic Layer Etching of Gold Using Sulfuryl Chloride for Chlorination and Triethylphosphine for Ligand Addition

Designing Volatile Molybdenum Compounds for Vapour-Phase Deposition

Atomic Layer Deposition of Molybdenum Carbide Thin Films

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