Effects of rapid thermal annealing on the contact of tungsten/p-diamond

• Published in: Applied surface science 2018-06, Vol.443, p.361-366
• Main Authors: Zhao, D., Li, F.N., Liu, Z.C., Chen, X.D., Wang, Y.F., Shao, G.Q., Zhu, T.F., Zhang, M.H., Zhang, J.W., Wang, J.J., Wang, W., Wang, H.X.
• Format: Article
• Language: English
• Subjects: Barrier height; Diamond; I-V; Ohmic contact; TLM; XPS
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.03.015

[Display omitted] •Contact properties of tungsten on p-type single crystal diamond have been investigated.•The specific contact resistance was extracted from fitting the I-V relationship of TLM.•The XPS measurements was used to explain the contact mechanism.•The tungsten carbide formation in W/p-diamond interface contributed to ohmic contact. The electrical properties, surface morphology and interface characteristics of W/p-diamond contact before and after annealing have been investigated. It is shown that the as-fabricated W/p-diamond contact exhibited non-linear behavior. After annealing at a temperature higher than 400 °C, the W/p-diamond contact showed ohmic behaviour. The specific contact resistance of W/p-diamond was 8.2 × 10−4 Ω·cm2 after annealing at 500 °C for 3 min in a N2 ambient, which was extracted from fitting the I-V relationship of TLM. It is noted that the RMS roughness increases with the annealing temperature increasing, which could be ascribed to the formation of WOX by the reaction of W and oxygen at high temperature. The XPS measurement showed that the barrier height of the W/p-diamond is 0.45 ± 0.12 eV after annealing at 500 °C. Furthermore, the formation of defects at the W/p-diamond interface, probably created by the formation of tungsten carbide during rapid thermal annealing, should be responsible for the ohmic formation of W/p-diamond after annealing at high temperature.