[15a-512-1~12] 3.7 Laser processing

[15a-512-7] The formation of Ni/Au ohmic contacts on p-type GaN by femtosecond laser annealing

Yuki Yamasaki¹, Hiroki Kawakami¹, Yoshiki Naoi¹, 〇Takuro Tomita¹ (1.Tokushima Univ.)

Keywords:femtosecond laser processing, GaN, wide band-gap semiconductor

Femtosecond laser beam was irradiated through the sapphire substrate at the interface between p-GaN and Ni/Au (20/20 nm) contact. The laser fluence was varied from 0.11 J/cm² to 0.28 J/cm². The current voltage characteristics of the irradiated contacts was evaluated by using two probes. The the contacts were 90 µm x 90 µm square shaped and the distance between the neighboring contacts was 90 µm. For the non-irradiated sample, the current voltage characteristics showed the Schottky characteristics. On the other hand, the ohmic characteristics was observed for the irradiation fluence ranging from 0.11 J/cm² to 0.28 J/cm². These results indicates that the ohmic contacts can be formed on p-GaN for the irradiation above the laser fluence of 0.10 J/cm².