We investigated the thermal stability of Pt/TaSi x /Ni/SiC ohmic contacts, which have been implemented in SiC-based gas sensors developed for applications in diesel engines and power plants. The contacts remained ohmic on lightly doped n-type (~1 × 1016 cm−3) 4H-SiC for over 1000 h in air at 300°C. Although a gradual increase in specific contact resistance from 3.4 × 10−4 Ω cm2 to 2.80 × 10−3 Ω cm2 was observed, the values appeared to stabilize after ~800 h of heating in air at 300°C. The contacts heated at 500°C and 600°C, however, showed larger increases in specific contact resistance followed by nonohmic behavior after 240 h and 36 h, respectively. Concentration profiles from Auger electron spectroscopy and electron energy-loss spectroscopy show that loss of ohmic behavior occurs when the entire tantalum silicide layer has oxidized.
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A. Lloyd Spetz, S. Savage, Recent Major Advances in SiC, W. J. Choyke, H. Matsunami, and G. Pensl, Eds. Berlin, Germany: Springer, 2003, pp.879–906
G. W. Hunter, P. G. Neudeck, J. Xu, D. Lukco, A. Trunek, M. Artale, P. Lampard, D. Androjna, D. Makel, B. Ward, C. C. Liu, Mat. Res. Soc. Symp. Proc. 815, J4.4.1 (2004).
H. Wingbrant, H. Svenningstorp, P. Salomonsson, P. Tengström, I. Lundström, A.L. Spetz, Sens. Actuators B Chem. 93, 1–3, 295–303 (2003). doi:10.1016/s0925-4005(03)00227-2
L.M. Porter, F.A. Mohommad, “Review of Issues Pertaining to the Development of Contacts to Silicon Carbide: 1996–2002,” in SiC MEMS for Harsh Environments, R.Cheung, Ed. London, England: Imperial College Press, 2006.
L.M. Porter, “Thermal stability and defects in contacts to silicon carbide” in Wide Band Gap Materials and New Developments, M. Syvajarvi and R. Yakimova, Eds. Kerala, India: Research Signpost, 2006.
H. Wingbrant, H. Svenningstorp, P. Salomonsson, D. Kubinski, J.H. Visser, M. Löfdahl, A.L. Spetz, IEEE Sens. J. 5, 1099–1105 (2005). doi:10.1109/JSEN.2005.854489
M. Andersson, L. Everbrand, A. Lloyd Spetz, T. Nyström, M.␣Nilsson, C. Gauffin, and H. Svensson, Proc. IEEE Sensors, October 28–31, 2007, Atlanta, USA, pp. 962–965.
J.R. Waldrop, R.W. Grant, Appl. Phys. Lett. 62, 2685–2687 (1993). doi:10.1063/1.109257
L.M. Porter, R.F. Davis, Mater. Sci. Eng. B B34, 83–105 (1995). doi:10.1016/0921-5107(95)01276-1
B. Barda, P. Machac, M. Hubičková, J. Náhlík, J. Mater. Sci. Mater. Electron. 19, 1039–1044 (2008). doi:10.1007/s10854-007-9446-7
G. Kelner, S. Binani, M. Shur, J.W. Palmour, Electron. Lett. 27, 1038–1040 (1991). doi:10.1049/el:19910646
S.-K. Lee, E.-K. Suh, N.-K. Cho, H.-D. Park, L. Uneus, A.L. Spetz, Solid-State Electron. 49, 1297–1301 (2005). doi:10.1016/j.sse.2005.06.005
S. Ezhilvalavan, T.Y. Tseng, J. Mater. Sci. Mater. Electron. 10, 9–31 (1999). doi:10.1023/A:1008970922635
R.S. Okojie, D. Lukco, Y.L. Chen, D.J. Spry, J. Appl. Phys. 91, 6553–6559 (2002). doi:10.1063/1.1470255
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Virshup, A., Porter, L.M., Lukco, D. et al. Investigation of Thermal Stability and Degradation Mechanisms in Ni-Based Ohmic Contacts to n-Type SiC for High-Temperature Gas Sensors. J. Electron. Mater. 38, 569–573 (2009). https://doi.org/10.1007/s11664-008-0609-y
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DOI: https://doi.org/10.1007/s11664-008-0609-y