Structural and Electrical Characterization of Ni-Based Ohmic Contacts on 4H-SiC Formed by Solid-State Laser Annealing

Abstract:

Laser annealing process for ohmic contact formation on 4H-SiC has attracted increasing attention in the last years, because it enables the fabrication of SiC power devices on very thin substrates. We have investigated the formation of Nickel-based ohmic contact on 4H-SiC by using a Yb:YAG laser in scanning mode, with a wavelength of 515 nm and a pulse duration of 1200 ns. A 100 nm thick Ni layer has been deposited on SiC and irradiated at different process conditions. The reaction process has been studied, as a function of fluence and scan number of laser annealing, by means of X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) analyses. The electrical properties of the annealed layers have been evaluated on Schottky Barrier Diodes (SBDs) devices, confirming the ohmic behavior of the reacted contact and showing improved performances respect to RTA approach. The compatibility of thermal budget of the process in the front side has been verified by means process simulation. A strong relationship between structural properties of reacted layers and electrical behavior of SBDs devices has been revealed. Solid-state laser annealing process, with wavelength in green light region, can indeed represent a suitable solution for ohmic contact formation of 4H-SiC power devices, fabricated on thin substrates.

• Periodical: Materials Science Forum (Volume 1062)
• Pages: 417-421
• DOI: https://doi.org/10.4028/p-x34i2i
• Online since: May 2022
• Authors: Paolo Badalà*, Emanuele Smecca, Simone Rascunà, Corrado Bongiorno, Egidio Carria, Anna Bassi, Gabriele Bellocchi, Silvia Castorina, Cristina Tringali, Antonino La Magna, Alessandra Alberti
• Keywords: 4H-SiC, Laser Annealing, Ohmic Contact, Power Device, Silicide, XRD

References

[1] F. Roccaforte, P. Fiorenza, G. Greco, R. Lo Nigro, F. Giannazzo, F. Iucolano, M. Saggio, Emerging trends in wide band gap semiconductors (SiC and GaN) technology for power devices, Microelectron. Eng. 187 (2018) 66-77.

DOI: 10.1016/j.mee.2017.11.021

[2] M. Mazzillo, A. Sciuto, G. Mannino, L. Renna, N. Costa, P. Badalà, Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers, Journal of Instrumentation, 11 (2016) P10010.

DOI: 10.1088/1748-0221/11/10/p10010

[3] S. Rascunà, P. Badalà, C. Tringali, C. Bongiorno, E. Smecca, A. Alberti, S. Di Franco, F. Giannazzo, G. Greco, F. Roccaforte, M. Saggio, Morphological and electrical properties of Nickel based Ohmic contacts formed by laser annealing process on n-type 4H-SiC, Materials Science in Semiconductor Processing, 97 (2019) 62-66.

DOI: 10.1016/j.mssp.2019.02.031

[4] A. Alberti, P. Badalà, G. Pellegrino, A. Santangelo, Structural and electrical characterization of silicided Ni/Au contacts formed at low temperature (< 300° C) on p-type [001] silicon, J. Appl. Phys., 110 (2011) 123510.

DOI: 10.1063/1.3670995

[5] P. Badalà, A. Santangelo, G. Pellegrino, A. Alberti, Silicided Au/Ni bilayer on p-type [001] silicon for low contact resistance metallization schemes, Microelectronic Engineering, 107 (2013) 196-199.

DOI: 10.1016/j.mee.2012.09.009

[6] P. Badalà, G. Faro, C. Marcellino, G. Pellegrino, A. Santangelo, A. Alberti, Structural characterization of in‐situ silicided contacts textured on p‐type [001] silicon, Phys. Status Solidi C, 11 (2014) 160-163.

DOI: 10.1002/pssc.201300132

[7] A. Alberti, P. Badalà and A. Santangelo, U.S. Patent 9,728,412 (2017).

[8] Z. Zhou, W. He, Z. Zhang, J. Sun, A. Schöner, Z. Zheng, Characteristics of Ni-based ohmic contacts on n-type 4H-SiC using different annealing methods, Nanotechnol. Precis. Eng., 4 (2021) 013006.

DOI: 10.1063/10.0003763

[9] P. Badalà, S. Rascunà, B. Cafra, A. Bassi, E. Smecca, M. Zimbone, C. Bongiorno, C. Calabretta, F. La Via, F. Roccaforte, M. Saggio, G. Franco, A. Messina, A. La Magna, A. Alberti, Ni/4H-SiC interaction and silicide formation under excimer laser annealing for ohmic contact, Materialia, 9 (2020) 100528.

DOI: 10.1016/j.mtla.2019.100528

[10] S. Sanzaro, C. Bongiorno, P. Badalà, A. Bassi, G. Franco, P. Vasquez, A. Alberti, A. La Magna, Inter-diffusion, melting and reaction interplay in Ni/4H-SiC under excimer laser annealing, Applied Surface Science, 539 (2021) 148218.

DOI: 10.1016/j.apsusc.2020.148218

[11] S. Sanzaro, C. Bongiorno, P. Badalà, A. Bassi, I. Deretzis, M. Enachescu, G. Franco, G. Fisicaro, P. Vasquez, A. Alberti, A. La Magna, Simulations of the ultra-fast kinetics in Ni-Si-C ternary systems under laser irradiation, Materials 14 (2021) 4769.

DOI: 10.3390/ma14164769