Interfacial stability of electroplated copper on a 5nm ruthenium film supported by silicon, Cu∕(5nmRu)∕Si, was investigated using Rutherford backscattering and high-resolution analytical electron microscopy. Transmission electron microscopy (TEM) imaging shows that a 5nm Ru film is amorphous in contrast to the columnar microstructures of thicker films (20nm). Direct Cu plating on a 5nm Ru film yielded a homogeneous Cu film with over 90% plating efficiency. It is demonstrated that 5nm Ru can function as a directly plateable Cu diffusion barrier up to at least 300°C vacuum anneal. TEM reveals an interlayer between Ru∕Si, which expands at the expense of Ru upon annealing. Electron energy loss spectroscopy analyses show no oxygen (O) across the Cu∕(5nmRu)∕Si interfaces, thereby indicating that the interlayer is ruthenium silicide (RuxSiy). This silicidation is mainly attributed to the failure of the ultrathin Ru barrier at the higher annealing temperature.
The interdiffusion of Hf and Si from high-κ gate dielectric candidate (HfO2)1−x(SiO2)x thin films deposited on Si (100) was studied using x-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, high resolution transmission electron microscopy, and Rutherford backscattering spectrometry in combination with chemical etching. After extreme rapid and conventional furnace thermal annealing treatments, Hf incorporation into Si is limited to less than 0.5–1 nm from the interface. Implications for high-κ gate dielectric applications are also discussed.
We present detailed B penetration studies from B-doped polysilicon through alternate gate dielectric candidate HfSixOy films. No detectible B penetration is observed for annealing times as long as 20 s after 950 °C. Considerable B incorporation into the Si substrate is observed for annealing temperatures higher than 950 °C. By modeling the B depth profiles, we calculated the B diffusivities through HfSixOy to be higher than the corresponding diffusivities for SiO2. B diffusion through grain boundaries after HfSixOy crystallization is proposed to be responsible for the enhanced B diffusivity observed.
Metal incorporation into silicon substrates, and thermal stability of alternate gate dielectric candidates HfSixOy and ZrSixOy films after aggressive thermal annealing are reported. Considerable Zr incorporation is observed after furnace and rapid thermal annealing. No detectible Hf incorporation is observed for HfSixOy films annealed with the same conditions as the ZrSixOy films. Sputter deposited Hf silicate films showed superior thermal stability compared with chemical vapor deposited Zr silicate films. An alternate approach to obtain sub-nm resolution depth profiling of impurities in Si is also reported. Device performance associated with Zr incorporation into the channel is also discussed.
We demonstrate that incorporating N in Hf-silicate films reduces B penetration through the dielectric film. By modeling the B depth profiles, we calculated the B diffusivities through Hf-silicate (HfSixOy) to be ∼2× higher than the corresponding diffusivities for Hf-silicon oxynitride (HfSixOyNz). B diffusion through grain boundaries after HfSixOy crystallization is believed to be responsible for the enhanced B diffusivity observed. Suppression of crystallization observed in HfSixOyNz films is attributed to the lower Hf content in the films and the incorporation of N. The decreased B penetration observed in HfSixOyNz is a combination of absence of grain boundaries and the fact that N blocks B diffusion by occluding diffusion pathways. The minimum temperatures for B penetration are estimated to be approximately 950 and 1050 °C for HfSixOy and HfSixOyNz, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.