Abstract
The mechanism of Ti/Al reaction to n-GaN was studied to form ohmic contacts with low contact resistivity. N-GaN layers with a carrier concentration of 2.17×1018 cm−3 were deposited on sapphire substrates. Ti/Al metals were deposited by conventional electron-beam techniques. Contact resistivity decreased as the Ti thickness increased, and increased as the Al thickness increased. The lowest contact resistivity was measured at 1.20 × 10−6 Ωcm2 for 80 nm Ti /100 nm Al. After annealing at 900 °C, Al/AlTi/TiN layers on GaN were formed and Al Ti alloy thickness decreased as Ti thickness increased, from 1.5 MeV Rutherford Backscattering Spectroscopy(RBS) measurement. It was found that the contact resistivity was reduced as alloy metal thickness into GaN was increased.
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Fukasawa, Y., Nakamura, T. & Nakamura, T. Ti/Al- GaN Reaction Mechanism Forming Low Contact Resistivity. MRS Online Proceedings Library 743, 1154 (2002). https://doi.org/10.1557/PROC-743-L11.54
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DOI: https://doi.org/10.1557/PROC-743-L11.54