Abstract
Ta/Au ohmic contacts are fabricated on n-type ZnO (∼1 × 1017 cm−3) epilayers, which were grown on R-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). After growth and metallization, the samples are annealed at 300°C and 500°C for 30 sec in nitrogen ambient. The specific contact resistance is measured to be 3.2×10−4 Ωcm2 for the as-deposited samples. It reduces to 5.4×10−6 Ωcm2 after annealing at 300°C for 30 sec without significant surface morphology degradation. When the sample is annealed at 500°C for 30 sec, the specific contact resistance increases to 3.3 × 10−5 Ωcm2. The layer structures no longer exist due to strong Au and Ta in-diffusion and O out-diffusion. The contact surface becomes rough and textured.
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Sheng, H., Emanetoglu, N.W., Muthukumar, S. et al. Ta/Au ohmic contacts to n-type ZnO. J. Electron. Mater. 32, 935–938 (2003). https://doi.org/10.1007/s11664-003-0226-8
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DOI: https://doi.org/10.1007/s11664-003-0226-8