A novel experiment approach to ohmic contact formation on p-doped SiC

• Main Authors: Vabres, Roberto, Bellocchi, Gabriele, Rascuna, Simone, Roccaforte, Fabrizio, Mancuso, Paola, Badala, Paolo, Puglisi, Valeria, Vivona, Marilena, Crupi, Isodiana
• Format: Conference Proceeding
• Language: English
• Subjects: Conductivity; Contact resistance; laser annealing; Lasers; ohmic contact; Ohmic contacts; Ovens; Resistance; Silicon carbide; Substrates; Temperature; Titanium
• ISSN: 2640-5563
• DOI: 10.1109/DCIS62603.2024.10769179

In this work, the fabrication of a novel configuration for an ohmic contact on p-doped SiC substrate, employing laser treatment instead of the conventional oven treatment, is analyzed. Test patterns made by Ti rectangular contacts on p-SiC were fabricated. The overall structure is treated with an excimer laser, employing different energy densities and number of shots. In particular, the laser energy density ranges from 1.0 \mathrm{~J} / \mathrm{cm}^{2} to 3.8 \mathrm{~J} / \mathrm{cm}^{2} and the number of shots from 1 to 10. The analysis shows that the system begins to exhibit an ohmic behavior when exposed to laser energy densities of 3.6 \mathrm{~J} / \mathrm{cm}^{2} and above. Also, the number of shots influences the electrical behavior, with higher values leading to losing the linearity in the I-V curves. The best performance, characterized by the lowest resistivity value, is observed with an energy density value of 3.8 \mathrm{~J} / \mathrm{cm}^{2} and 1 laser shot applied. Under these conditions, the resistivity value is 1.4 \times 10^{-2} \Omega \mathrm{~cm}, or in terms of specific resistivity 7 \times 10^{-5} \mathbf{R c m}^{2}, the contact resistance is 152 \Omega and the sheet resistance is \mathbf{6 5 6} \Omega / \mathrm{sq}. This work enables the achievement of an ohmic contact between Titanium and p doped SiC, overcoming the challenge of using high temperature oven treatment.