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

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.