In this paper, we present results on the formation of He-cavities in Si in the presence of vacancies and hydrogen produced by electron cyclotron resonance (ECR) high-density hydrogen plasma treatment. Epitaxial Si (111) samples were first implanted with 1.55 MeV He ions at a dose of 5´10 16 cm -2 . Subsequent annealing at 800 °C for 30 min creates a band of cavities around the He projected range. This band is mainly made up of big elongated cavities in the middle surrounded by a high density of small ones. Other defects (mainly dislocations) have also been observed within and beneath the cavity band. Additional hydrogen plasma treatment, however, changes the morphology of the He-cavities. Plasma hydrogenation tends to increase both the width of cavity band and the cavity size, while, the density of cavities decreases. Moreover, with the plasma hydrogenation step, the cavities are accompanied by a significant concentration of dislocation loops. Such effects have been interpreted in terms of the vacancy-type defects and atomic hydrogen introduced by plasma hydrogenation, and thus their interactions with He-cavities. We have confirmed the generation of high concentrations of vacancies by hydrogen plasma treatment through positron annihilation spectroscopy (PAS) measurements.
Nickel silicide (NiSi) offers the advantages of lower processing temperature, reduced silicon consumption in silicide formation, and absence of bridging failures and is hence expected to replace Ti and Co silicides as contact material in Si microelectronics. In this article, we report on our work involving the study of hydrogen plasma pretreatment of the Si substrate on the properties of subsequently formed NiSi. We observe the sheet resistance of the silicide film to decrease with hydrogenation at the expected lower processing temperatures of 400 and 500°C. Transmission electron microscopy studies do reveal that defects are introduced near the silicide-silicon interface in the hydrogenated wafers at lower processing temperatures. But these defects are annealed out at higher processing temperatures. Secondary ion mass spectroscopy profiles show an enhanced diffusion of Ni into the Si substrate at 500 and 600°C, apparently due to the defects introduced in the substrate by the hydrogen treatment.
The formation of subsurface nm-size cavities in Si from He implantation followed by thermal anneal involves a complex interaction of He with vacancy clusters. We have attempted to promote cavity formation with vacancy-type defects arising from a hydrogen plasma treatment that is interposed between the implantation (40 keV and 160 keV He) and anneal (800 \degresC-1 h) steps. Cross-sectional transmission electron microscopy (XTEM) results show enhanced growth of He-induced cavities due to hydrogen in the 160 keV He implanted sample, while no significant change is seen in the cavity spectrum for 40 keV. In conjunction with Secondary Ion Mass Spectroscopy (SIMS) data, the results are tentatively interpreted in terms of the evolution of defects and hydrogen during annealing, their interactions with the He-cavities, and proximity of the layers to the surface
The ability to activate large concentrations of boron at lower temperatures is a persistent contingency in the continual drive for device scaling in Si microelectronics. We report on our experimental observations offering evidence for enhancement of electrical activation of implanted boron dopant in the presence of atomic hydrogen in silicon. This increased electrical activity of boron at lower anneal temperature is attributed to the creation of vacancies in the boron-implanted region, lattice-relaxation caused by the presence of atomic hydrogen, and the effect of atomic hydrogen on boron-interstitial cluster formation.
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.