Thermal Annealing effects study on electrical and structural properties for Ni-Au/n-GaN Schottky Contacts

摘要

The effects of thermal annealing on the electrical and interfacial structure properties of Ni/Au on n-type GaN Schottky contacts were investigated by current-voltage (I-V). Based on the I-V measurement study, it was found that the Schottky barrier height increased when the contact was annealed in the 300°C – 400°C temperature range. A drastic improvement of the Schottky barrier height was attained by thermal annealing at 400°C for 10 minutes. However, it degraded when the annealing temperature exceeded 500°C. The contact annealed at 550°C showed nonrectifying behavior. For this paper, the GaN metal-semiconductor-metal (MSM) ultraviolet photodetectors were fabricated using Ni/Au Schottky contacts. As expected, compared with the MSM detector without the thermal annealing process, the dark current of the MSM device with the 400°C thermal annealing process drastically decreased as much as three orders of magnitude, due to the enhancement of the Schottky barrier height.