IMPACT OF NANOSECOND LASER ENERGY DENSITY ON THE C40-TiSi2 FORMATION AND C54-TiSi2 TRANSFORMATION TEMPERATURE. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Applied Physics Année : 2020

IMPACT OF NANOSECOND LASER ENERGY DENSITY ON THE C40-TiSi2 FORMATION AND C54-TiSi2 TRANSFORMATION TEMPERATURE.

Résumé

The formation of Ti based contacts in new image sensors CMOS technologies is limited by the requirement of low thermal budget. The objectives for these new 3D-technologies are to promote ohmic, low resistance, repeatable and reliable contacts by keeping the process temperature as low as possible. In this work, UV-nanosecond laser annealing were performed before classical rapid thermal annealing (RTA) to promote the formation at lower RTA temperatures of the low resistivity C54-TiSi2 phase. The laser energy density was varied from 0.30 to 1.00 J/cm² with 3 pulses in order to form the C40-TiSi2 phase and finally to obtain the C54-TiSi2 phase by a subsequent RTA at low temperature. The formed Ti-silicides were characterized by four-point probe measurements, X-Ray Diffraction, Transmission Electron Microscopy and Atom Probe Tomography. A threshold in the laser energy density for the formation of the C40-TiSi2 is observed at an energy density of 0.85 J/cm² for the targeted TiN/Ti stack on blanket wafers. The C40-TiSi2 formation by laser annealing prior to RTA enables to reduce the formation temperature of the C54-TiSi2 phase by 150°C in comparison to a single RTA applied after the Ti/TiN deposition. This specific phase sequence is only observed for a laser energy density close to 0.85 J/cm². At higher energy densities, the presence of C49-TiSi2 or a mix of C49-TiSi2 and C54-TiSi2 is observed. The underlying mechanisms for the phase sequence and formation are discussed in details.

Domaines

Matériaux
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Dates et versions

hal-02922876 , version 1 (26-08-2020)

Identifiants

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Laura Esposito, S. Kerdiles, M. Gregoire, P. Benigni, K. Dabertrand, et al.. IMPACT OF NANOSECOND LASER ENERGY DENSITY ON THE C40-TiSi2 FORMATION AND C54-TiSi2 TRANSFORMATION TEMPERATURE.. Journal of Applied Physics, 2020, 128 (8), pp.085305. ⟨10.1063/5.0016091⟩. ⟨hal-02922876⟩
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