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

Abstract

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 J/cm2 to 3.8 J/cm2 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 J/cm2 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 J/cm2 and 1 laser shot applied. Under these conditions, the resistivity value is 1.4x10-2 Ωcm, or in terms of specific resistivity 7x10-5 Ωcm2, the contact resistance is 152 Ω and the sheet resistance is 656 Ω/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.