(Invited) Contacts in Advanced CMOS: History and Emerging Challenges

Lavoie, C.; Adusumilli, Praneet; Carr, Adra; Sweet, Jean S. Jordan; Özcan, Ahmet; Levrau, Elisabeth; Breil, N.; Alptekin, Emre

doi:10.1149/07705.0059ecst

Cited by 33 publications

(18 citation statements)

References 30 publications

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“…The stable phase, C54-TiSi2, with a low resistivity (15-20 µΩ.cm), is formed from C49-TiSi2 at higher temperatures between 700 and 850°C 7,[9][10][11] . For advanced imagers technologies as well as 3D FinFETs, TiSi2 contacts are formed through the "salicide last" process with a single-step RTA at high temperature without any selective etch of the unreacted Ti layer 12,13 . This is different from the "salicide first" process which implies two RTA (the first one at low temperature and the second at high temperature) with a selective etch of the unreacted metal between the two RTA steps 7 .…”

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

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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.

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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

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“…The CN films clearly display a D-and a dominating G-peak at all temperatures showing a higher content of sp 2 -bonds [42]. The C≡N peak in the Raman spectrum indicates that spbonded N is incorporated into the film, but also sp 2 -and sp 3 -bonds between C and N are formed during the sputter process.…”

Section: Sputtered Carbon -Process and Propertiesmentioning

confidence: 95%

“…Metal to semiconductor contacts are essential elements in integrated and discrete electronic devices. Common source and drain contacts in state-of-the-art FinFETs rely on the formation of titanium silicide (TiSi) [1]- [3]. TiSi provides a very low Schottky barrier height (SBH) to silicon, that's why it is also highly appropriate for Schottky diodes in zero bias detector and mixer applications up to THz frequencies [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Highly Reliable Contacts to Silicon Enabled by Low Temperature Sputtered Graphenic Carbon

Stelzer

Jung

Wurstbauer

et al. 2019

IEEE J. Electron Devices Soc.

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Titanium silicide (TiSi) contacts are frequently used metal-silicon contacts but are known to diffuse into the active region under high current density stress pulses. Recently, we demonstrated that graphenic carbon (GC) deposited by CVD at 1000 • C on silicon has the same low Schottky barrier as TiSi, but a much improved reliability against high current density stress pulses. In this paper, we demonstrate now that the deposition of GC is possible at 100 • C − 400 • C by a sputter process. We show that the sputtered carbon-silicon contact is over 1 billion times more stable against high current density pulses than the conventionally used TiSi-Si junction, while it has the same or even a lower Schottky barrier. SC can be doped by nitrogen (CN) and this results in an even lower resistivity and improved stability. Scalability of the CN thickness down to 5 nm is demonstrated. The finding that there is a low temperature approach for using the excellent carbon properties has important consequences for the reliability of contacts to silicon and opens up the use of GC in a vast number of other applications.

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“…The electrical and thermal contact resistance of the metal electrodes are special issues for measurement which have severe impacts on the nanodevice performance which mean that ohmic contacts are necessary. Following the scaling of IC-technology, different metal electrodes have been experimented on for the contact resistance with the tendency of TiSi 2 → CoSi 2 → Ni(Pt)Si in planar structures (Lavoie et al, 2017). For the fabrication of µTEG integrated with a heater, Pt is a good choice for both electrodes and heaters due to its thermal-independence FIGURE 13 | 3ω-scanning thermal microscopy measurement.…”

Section: Thermal and Electrical Contact Resistancementioning

confidence: 99%

Si and SiGe Nanowire for Micro-Thermoelectric Generator: A Review of the Current State of the Art

et al. 2021

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In our environment, the large availability of wasted heat has motivated the search for methods to harvest heat. As a reliable way to supply energy, SiGe has been used for thermoelectric generators (TEGs) in space missions for decades. Recently, micro-thermoelectric generators (μTEG) have been shown to be a promising way to supply energy for the Internet of Things (IoT) by using daily waste heat. Combining the predominant CMOS compatibility with high electric conductivity and low thermal conductivity performance, Si nanowire and SiGe nanowire have been a candidate for μTEG. This review gives a comprehensive introduction of the Si, SiGe nanowires, and their possibility for μTEG. The basic thermoelectric principles, materials, structures, fabrication, measurements, and applications are discussed in depth.

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(Invited) Contacts in Advanced CMOS: History and Emerging Challenges

Cited by 33 publications

References 30 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

Highly Reliable Contacts to Silicon Enabled by Low Temperature Sputtered Graphenic Carbon

Si and SiGe Nanowire for Micro-Thermoelectric Generator: A Review of the Current State of the Art

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