Additional Siconi™ pre-clean for reliable TiSix contacts in advanced imager technologies

Gregoire, M.; Horvat, Berislav; Bozon, B.N.; Combe, D.; Dabertrand, K.; Roy, D.

doi:10.1016/j.mne.2019.02.001

Cited by 4 publications

(1 citation statement)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As devices sizes are aggressively scaled, the NiPt silicides are widely present in planar technologies 1 . However, they have been replaced by Ti-based silicides in recent contacts for 3D FinFETs (Fin-type Field Effect Transistor) technologies and image sensor CMOS technologies in order to achieve a very low Resistance Capacitance (RC) delay values and high device performances [2][3][4][5][6] . After usual Rapid Thermal Annealing (RTA) in the 550-950°C temperature range, two phases of titanium disilicides (TiSi2) could exist.…”

Section: Introductionmentioning

confidence: 99%

Impact of nanosecond laser energy density on the C40-TiSi2 formation and C54-TiSi2 transformation temperature

Esposito

Kerdilès

Gregoire

et al. 2020

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Impact of nanosecond laser energy density on the C40-TiSi2 formation and C54-TiSi2 transformation temperature

Esposito

Kerdilès

Gregoire

et al. 2020

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

show abstract

C54-TiSi2 formation using nanosecond laser annealing of A-Si/Ti/A-Si stacks

Guelladress,

Kerdilès,

Dartois

et al. 2024

Thin Solid Films

View full text Add to dashboard Cite

Gas-phase etching mechanism of silicon oxide by a mixture of hydrogen fluoride and ammonium fluoride: A density functional theory study

Hidayat

Khumaini

Kim

et al. 2023

Journal of Vacuum Science &Amp; Technology A

View full text Add to dashboard Cite

We report the selective etching mechanism of silicon oxide using a mixture of hydrogen fluoride (HF) and NH4F gases. A damage-free selective removal of native oxide has been used in semiconductor manufacturing by forming and removing the ammonium fluorosilicate [(NH4)2SiF6] salt layer. A downstream plasma of NF3/NH3 or a gas-phase mixture of HF and NH4F was used to form (NH4)2SiF6. We modeled and simulated the fluorination of silicon oxide and the salt formation by density functional theory calculation. First, we simulated the successive fluorination of silicon oxide using SiO2 slab models. The fluorination reactions of SiO2 surfaces by the mixture produced a volatile SiF4 molecule or a surface anion of –OSiF4−* with an NH4+ cation with low activation energies. Unlike HF, NH4F produced surface salt species consisting of a surface anion and an ammonium cation. Next, we simulated the (NH4)2SiF6 formation from the two reaction products on fluorinated SiO2 surfaces. (NH4)2SiF6 can be formed exothermally with low activation energies (0.27 or 0.30 eV). Finally, we compared silicon with SiO2 to demonstrate the inherently selective etching of silicon oxide. The fluorination reactions of silicon by the mixture showed the activation energies significantly higher than the SiO2 cases, 1.22–1.56 eV by HF and 1.94–2.46 eV by NH4F due to the less stable transition state geometries. Therefore, the selective salt formation on silicon oxide, not on silicon, is expected in near-room temperature processing, which enables selective etching of silicon oxide.

show abstract

Additional Siconi™ pre-clean for reliable TiSix contacts in advanced imager technologies

Cited by 4 publications

References 11 publications

Impact of nanosecond laser energy density on the C40-TiSi2 formation and C54-TiSi2 transformation temperature

Impact of nanosecond laser energy density on the C40-TiSi2 formation and C54-TiSi2 transformation temperature

C54-TiSi2 formation using nanosecond laser annealing of A-Si/Ti/A-Si stacks

Gas-phase etching mechanism of silicon oxide by a mixture of hydrogen fluoride and ammonium fluoride: A density functional theory study

Contact Info

Product

Resources

About