Advanced precursor design for atomic layer deposition and chemical vapour deposition of gold metal
Bibliographic record
Abstract
This thesis first outlines the current state-of-the-art of gold CVD and ALD precursors based on their precursor figures of merit (σ) which was a concept developed in this research program.Then, this thesis demonstrates the ability to control the structure of deposited nanoparticles by CVD, using a combination of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) to elucidate the mechanism of growth.This represents one of the first gold CVD studies to rationally design a precursor that would deposit anisotropic nanostructures.This thesis then describes the first gold ALD process (PMe3)AuMe3.Then, a new process using this same precursor and hydrogen plasma was developed and the surface mechanism of this new ALD process was investigated using a combination of in-situ reflection absorption infrared spectroscopy (RAIRS), XPS, and quadrupole mass spectrometry (QMS).This mechanistic study provides insight on the kinetics of Me and PMe3 ligand desorption from the surface and re-defines the upper limit of the Au ALD process.In order to improve on the existing state-of-the-art of gold precursors, this thesis then describes a systematic gold(I) precursor design.Using a combination of TGA, differential scanning calorimetry (DSC), x-ray crystallography, and density functional theory (DFT), we delineate why certain ligands work well for gold(I) and we develop the precursor figure of merit (σ) in this chapter.With a knowledge of the design factors that make a good precursor from the standpoint of thermolysis, this thesis then describes a study where the rate of CVD of various gold(I) precursors is compared by in situ monitoring using a combination of quartz crystal microbalance (QCM) and quadrupole mass spectrometry (QMS).This study culminates in a new idea in the field of ALD: the rational design of a kinetically limited ALD process.We then show that the kinetic implications of steric bulk that are ubiquitous in solution-phase synthetic chemistry can also be exploited in the fields of CVD and ALD.Finally, this thesis describes a study where an alkylgold(I) NHC self-limiting precursor is rationally designed.A family of these types of precursors is presented, and the self-limiting capability of these precursors is demonstrated using our in-situ QCM/QMS monitoring apparatus.We then show that highly conductive and high-purity gold thin films can be deposited with one of these new precursors, and the film's purity (>99% by XPS) and resistivity (4.2 µΩ cm) rival the current state of the art of Au ALD films.Altogether, this thesis demonstrates that the rational design of deposition precursors is essential to the advancement of the fields of CVD and ALD not only for the development of new processes, but also because of the importance of the precursor on growth morphology.Being able to tailor a compound for a specific thin film material is important not only for gold thin films, but also for the rest of the periodic table, as well as new materials that have not yet been synthesized.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".