Ni silicide formation on epitaxial Si1-yCy/(001) layers

Metallization of silicon solar cells using electroplating is of interest recently as a cheaper replacement of silver screen printing. Light assisted electroplating of Nickel-Cobalt (NiCo) alloys were studied on crystalline silicon (Si) solar cells in this paper. The effect of illumination was investigated in conjunction with the light absorption properties of the plating solution, emission spectrum of the light source as well as the plating current. A solution dependent threshold light intensity was observed, beyond which the solar cells were under reverse bias during electroplating. The detailed compositional depth profiles of the silicide layer were studied along the silicidation reaction using microscopic energy dispersive X-ray spectrum (EDS). A significant improvement in the performance degradation at high temperature thermal stress was observed for solar cells metalized with the ternary silicide. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0191602jss] All rights reserved.

A Study on the Electrodeposition and Silicidation of Nickel-Cobalt Alloys for Silicon Photovoltaic Cell Metallization

Platinum silicide formation on Si1−yCy epitaxial layers

We present a systematic study on the effects of CF4 plasma immersion ion implantation (PIII) in Si on the phase evolution of ultra-thin Ni silicides. For 3 nm Ni, NiSi2 was formed on Si substrates with and without CF4 PIII at temperature as low as 400 °C. For 6 nm Ni, NiSi was formed on pure Si, while epitaxial NiSi2 was obtained on CF4 PIII Si. The incorporation of C and F atoms in the thin epitaxial NiSi2 significantly reduces the layer resistivity. Increasing the Ni thickness to 8 nm results in the formation of NiSi, where the thermal stability of NiSi, the NiSi/Si interface and Schottky contacts are significantly improved with CF4 PIII. We suggest that the interface energy is lowered by the F and C dopants present in the layer and at the interface, leading to phase evolution of the thin Ni silicide.

https://iopscience.iop.org/article/10.1088/1361-6528/ab6d21/pdf

Phase evolution of ultra-thin Ni silicide films on CF4 plasma immersion ion implanted Si.

This chapter starts the discussion about size effect in physical and other (except electrochemical and mechanical) properties of nanocoatings and its real usage through different examples. It starts from the usage of nanostructured materials in microelectronics and goes through different reported papers in this field. Size effect in nanometric scale has been compared with larger scales by some examples. Detailed discussions about some methods with enough examples were presented in this chapter. Different parts of this chapter include discussions about microelectronics, silicides specifications, size effect in sensing characterization, size effect in optical properties of nanostructured films, self-cleaning glasses, using nanocomposite coating for food packaging and using polarizer nano-layers to produce LCD monitors.

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Size Effect in Physical and Other Properties of Nanostructured Coatings

This study investigates the formation of Ni silicides on Si 1-y C y (0 ≤ y ≤ 0.02) epilayers grown on Si(001). The presence of C atoms retards the growth kinetics of NiSi and significantly enhances the thermal stability of NiSi thin films. In particular, an abnormal redistribution of C atoms in the NiSi thin films was observed during Ni silicidation. The NiSi layer was split into two sublayers by an obvious pileup of C atoms. This study proposes a mechanism to elucidate this phenomenon in terms of the C solubility. C atoms accumulated at the NiSi/S 1-y C y interfaces and NiSi grain boundaries may act as diffusion barriers, effectively hindering the grain growth and agglomeration of NiSi and extending the process window of low resistivity NiSi silicides.

C. P. Lo

Papers

C Redistribution during Ni Silicide Formation on Si1 − y C y Epitaxial Layers