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Zaera F. The surface chemistry of the atomic layer deposition of metal thin films. NANOTECHNOLOGY 2024; 35:362001. [PMID: 38888294 DOI: 10.1088/1361-6528/ad54cb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 06/06/2024] [Indexed: 06/20/2024]
Abstract
In this perspective we discuss the progress made in the mechanistic studies of the surface chemistry associated with the atomic layer deposition (ALD) of metal films and the usefulness of that knowledge for the optimization of existing film growth processes and for the design of new ones. Our focus is on the deposition of late transition metals. We start by introducing some of the main surface-sensitive techniques and approaches used in this research. We comment on the general nature of the metallorganic complexes used as precursors for these depositions, and the uniqueness that solid surfaces and the absence of liquid solvents bring to the ALD chemistry and differentiate it from what is known from metalorganic chemistry in solution. We then delve into the adsorption and thermal chemistry of those precursors, highlighting the complex and stepwise nature of the decomposition of the organic ligands that usually ensued upon their thermal activation. We discuss the criteria relevant for the selection of co-reactants to be used on the second half of the ALD cycle, with emphasis on the redox chemistry often associated with the growth of metallic films starting from complexes with metal cations. Additional considerations include the nature of the substrate and the final structural and chemical properties of the growing films, which we indicate rarely retain the homogeneous 2D structure often aimed for. We end with some general conclusions and personal thoughts about the future of this field.
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Affiliation(s)
- Francisco Zaera
- Department of Chemistry, University of California, Riverside, CA 92521, United States of America
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Ogunfowora LA, Singh I, Arellano N, Pattison TG, Magbitang T, Nguyen K, Ransom B, Lionti K, Nguyen S, Topura T, Delenia E, Sherwood M, Savoie BM, Wojtecki R. Reactive Vapor-Phase Inhibitors for Area-Selective Depositions at Tunable Critical Dimensions. ACS APPLIED MATERIALS & INTERFACES 2024; 16:5268-5277. [PMID: 38206307 DOI: 10.1021/acsami.3c14821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Area-selective depositions (ASD) take advantage of the chemical contrast between material surfaces in device fabrication, where a film can be selectively grown by chemical vapor deposition on metal versus a dielectric, for instance, and can provide a path to nontraditional device architectures as well as the potential to improve existing device fabrication schemes. While ASD can be accessed through a variety of methods, the incorporation of reactive moieties in inhibitors presents several advantages, such as increasing thermal stability and limiting precursor diffusion into the blocking layer. Alkyne-terminated small molecule inhibitors (SMIs)─propargyl, dipropargyl, and tripropargylamine─were evaluated as metal-selective inhibitors. Modeling these SMIs provided insight into the binding mechanism, influence of sterics, and complex polymer network formed from the reaction between inhibitors consisting of alkene, aromatic, and network branchpoints. While a significant contrast in the binding of the SMIs on copper versus a dielectric was observed, residual amounts were detected on the dielectric surfaces, leading to variable ALD growth rates dependent on pattern-critical dimensions. This behavior can be controlled and utilized to direct film growth on patterns only above a critical threshold dimension; below this threshold, both the dielectric and metal features are protected. This method provides another design parameter for ASD processes and may extend its application to broader-ranging device fabrication schemes.
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Affiliation(s)
- Lawal Adewale Ogunfowora
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Ishwar Singh
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Noel Arellano
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Thomas G Pattison
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Teddie Magbitang
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Khanh Nguyen
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Brandi Ransom
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Krystelle Lionti
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Son Nguyen
- International Business Machines─Semiconductor Technology Research, Albany, New York 12203, United States
| | - Teya Topura
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Eugene Delenia
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Mark Sherwood
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
| | - Brett M Savoie
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rudy Wojtecki
- International Business Machines─Almaden Research Center, San Jose, California 95120, United States
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