Achieving historically anticipated improvement in the performance of integrated circuits is challenging,due to the increasing cost and complexity of the required technologies with each new generation.To overcome this ...Achieving historically anticipated improvement in the performance of integrated circuits is challenging,due to the increasing cost and complexity of the required technologies with each new generation.To overcome this limitation,the exploration and development of novel interconnect materials and processes are highly desirable in the microelectronics field.Molybdenum(Mo)is attracting attention as an advanced interconnect material due to its small resistivity size effect and high cohesive energy;however,effective processing methods for such materials have not been widely investigated.Here,we investigate the electrochemical behavior of ions in the confined nanopores that affect the electrical properties and microstructures of nanoscale Mo and Mo-Co alloys prepared via template-assisted electrodeposition.Additives in an electrolyte allow the deposition of extremely pure metal materials,due to their interac-tion with metal ions and nanopores.In this study,boric acid and tetrabutylammonium bisulfate(TBA)were added to an acetate bath to inhibit the hydrogen evolution reaction.TBA accelerated the reduction of Mo at the surface by inducing surface conduction on the nanopores.Metallic Mo nanowires with a 130 nm diameter synthesized through high-aspect-ratio nanopore engineering exhibited a resistivity of(63.0±17.9)μΩcm.We also evaluated the resistivities of Mo-Co alloy nanowires at various compo-sitions toward replacing irreducible conventional barrier/liner layers.An intermetallic compound formed at a Mo composition of 28.6 at%,the resistivity of the Mo-Co nanowire was(58.0±10.6)μΩcm,indicat-ing its superior electrical and adhesive properties in comparison with those of conventional barriers such as TaN and TiN.Furthermore,density functional theory and non-equilibrium Green's function calcula-tions confirmed that the vertical resistance of the via structure constructed from Mo-based materials was 21%lower than that of a conventional Cu/Ta/TaN structure.展开更多
Developing highly efficient electrochemical catalysts for carbon dioxide reduction reaction(CO_(2)RR)provides a solution to battle global warming issues resulting from ever-increasing carbon footprint due to human act...Developing highly efficient electrochemical catalysts for carbon dioxide reduction reaction(CO_(2)RR)provides a solution to battle global warming issues resulting from ever-increasing carbon footprint due to human activities.Copper(Cu)is known for its efficiency in CO_(2)RR towards value-added hydrocarbons;hence its unique structural properties along with various Cu alloys have been extensively explored in the past decade.Here,we demonstrate a two-step approach to achieve intimate atomic Cu-Ag interfaces on the surface of Cu nanowires,which show greatly improved CO_(2)RR selectivity towards methane(CH4).The specially designed Cu-Ag interfaces showed an impressive maximum Faradaic efficiency(FE)of 72%towards CH4 production at-1.17 V(vs.reversible hydrogen electrode(RHE)).展开更多
The thermal decomposition synthesis of long copper nanowires （CuNWs） was achieved by controlling the synthesis parameters. A detailed study was performed to determine the effect of the molar ratio of copper chloride...The thermal decomposition synthesis of long copper nanowires （CuNWs） was achieved by controlling the synthesis parameters. A detailed study was performed to determine the effect of the molar ratio of copper chloride to nickel acetylacetonate, temperature, and stirring rate on the final shape of the products. Transparent electrodes （TEs） were fabricated by wet treatment with acetic acid （AA）, without using a sintering process. The low oxidation stability and high surface roughness are the main disadvantages of the CuNW TEs, which limit their applications. In order to overcome these issues, we prepared CuNW/polymer composite TEs by partial embedding of the CuNWs into poly（methyl methacrylate） （PMMA） on poly（ethylene terephthalate） （PET） substrates. The CuNW/PMMA composite TEs exhibit excellent optoelectronic performance （91.3% at 100.7 ff2/sq）, low surface roughness （4.6 nm in height）, and good mechanical and chemical stability as compared with CuNW TEs. On the basis of these properties, we believe that CuNW-based composite TEs could serve as low-cost materials for a wide range of new optoelectronic devices.展开更多
基金supported by the Basic Science Research Program of the National Research Foundation of Koreafunded by the Ministry of Education of the Republic of Korea(2021R1A6A3A13046504)+1 种基金the Ministry of Science and ICT of the Republic of Korea(2022M3H4A1A04096339 and 2020M3F3A2A01081585)the Samsung Electronics Co.,Ltd.(IO210317-08500-01).
文摘Achieving historically anticipated improvement in the performance of integrated circuits is challenging,due to the increasing cost and complexity of the required technologies with each new generation.To overcome this limitation,the exploration and development of novel interconnect materials and processes are highly desirable in the microelectronics field.Molybdenum(Mo)is attracting attention as an advanced interconnect material due to its small resistivity size effect and high cohesive energy;however,effective processing methods for such materials have not been widely investigated.Here,we investigate the electrochemical behavior of ions in the confined nanopores that affect the electrical properties and microstructures of nanoscale Mo and Mo-Co alloys prepared via template-assisted electrodeposition.Additives in an electrolyte allow the deposition of extremely pure metal materials,due to their interac-tion with metal ions and nanopores.In this study,boric acid and tetrabutylammonium bisulfate(TBA)were added to an acetate bath to inhibit the hydrogen evolution reaction.TBA accelerated the reduction of Mo at the surface by inducing surface conduction on the nanopores.Metallic Mo nanowires with a 130 nm diameter synthesized through high-aspect-ratio nanopore engineering exhibited a resistivity of(63.0±17.9)μΩcm.We also evaluated the resistivities of Mo-Co alloy nanowires at various compo-sitions toward replacing irreducible conventional barrier/liner layers.An intermetallic compound formed at a Mo composition of 28.6 at%,the resistivity of the Mo-Co nanowire was(58.0±10.6)μΩcm,indicat-ing its superior electrical and adhesive properties in comparison with those of conventional barriers such as TaN and TiN.Furthermore,density functional theory and non-equilibrium Green's function calcula-tions confirmed that the vertical resistance of the via structure constructed from Mo-based materials was 21%lower than that of a conventional Cu/Ta/TaN structure.
基金TEM work was conducted using the facilities in the electron imaging center of California NanoSystems Institute at the University of California Los Angles and the Irvine Materials Research Institute at the University of California Irvine.C.C.,J.C.and Y.H.acknowledge support by the Office of Naval Research(ONR)(No.N000141712608)C.S.L.and H.M.L.acknowledge support by a National Research Foundation(NRF)of Korea grant funded by the Korean Government(Nos.NRF-2017 R1E1A1A03071049 and NRF-2020R1A5A6017701).
文摘Developing highly efficient electrochemical catalysts for carbon dioxide reduction reaction(CO_(2)RR)provides a solution to battle global warming issues resulting from ever-increasing carbon footprint due to human activities.Copper(Cu)is known for its efficiency in CO_(2)RR towards value-added hydrocarbons;hence its unique structural properties along with various Cu alloys have been extensively explored in the past decade.Here,we demonstrate a two-step approach to achieve intimate atomic Cu-Ag interfaces on the surface of Cu nanowires,which show greatly improved CO_(2)RR selectivity towards methane(CH4).The specially designed Cu-Ag interfaces showed an impressive maximum Faradaic efficiency(FE)of 72%towards CH4 production at-1.17 V(vs.reversible hydrogen electrode(RHE)).
文摘The thermal decomposition synthesis of long copper nanowires （CuNWs） was achieved by controlling the synthesis parameters. A detailed study was performed to determine the effect of the molar ratio of copper chloride to nickel acetylacetonate, temperature, and stirring rate on the final shape of the products. Transparent electrodes （TEs） were fabricated by wet treatment with acetic acid （AA）, without using a sintering process. The low oxidation stability and high surface roughness are the main disadvantages of the CuNW TEs, which limit their applications. In order to overcome these issues, we prepared CuNW/polymer composite TEs by partial embedding of the CuNWs into poly（methyl methacrylate） （PMMA） on poly（ethylene terephthalate） （PET） substrates. The CuNW/PMMA composite TEs exhibit excellent optoelectronic performance （91.3% at 100.7 ff2/sq）, low surface roughness （4.6 nm in height）, and good mechanical and chemical stability as compared with CuNW TEs. On the basis of these properties, we believe that CuNW-based composite TEs could serve as low-cost materials for a wide range of new optoelectronic devices.
