On The Schottky Barrier Height Lowering Effect of Ti3SiC2 in Ohmic Contacts to P-Type 4H-SiC
Keywords:4H-SiC, ohmic contact, p-type, Ti3SiC2
In this paper, an experimental investigation into titanium (Ti) / aluminium (Al)-based ohmic contacts to p-type 4H-silicon carbide (SiC) has been presented. Electrical characterisation of the fabricated contacts showed that metal structures with an initial Ti layer yielded the lowest specific contact resistance (ρc), with a mean value of 3.7×10-5 Ω-cm2 being achieved after annealing in argon (Ar) at 1000°C for 2 minutes. Transmission electron microscopy (TEM) analysis illustrated the epitaxial relationship between the 4H-SiC and the as-deposited Ti layer, and, in conjunction with energy dispersive X-ray (EDX) analysis, showed that after annealing a ~5 nm thick layer of Ti3SiC2 was present, epitaxially arranged with the 4H-SiC. X-ray diffraction (XRD) analysis showed that the presence of the Ti3SiC2 metallic phase was more prevalent in the samples with Ti as the initial metal layer annealed at 1000°C, which corresponded with lower specific contact resistance. Fitting of experimental data to a thermionic field emission (TFE) model allowed the Schottky barrier height to be extracted; it was found that the lowest Schottky barrier heights were more prevalent where the most intense Ti3SiC2 phases were observed during XRD analysis.
Buchholt, K., Ghandi, R., Domeij, M., Zetterling, C.-M., Lu, J., Eklund, P., Spetz, A. L. (2011). Ohmic contact properties of magnetron sputtered Ti 3 SiC 2 on n-and p-type 4H-silicon carbide. Applied physics letters, 98(4), 042108-042108-042103.
Buttay C, P. D., Allard B, Bergogne D, Bevilacqua P, Joubert, Lazar M, Martin C, Morel H, Tournier D, Raynaud C. (2011). State of the art of High Temperature Power Electronics. Materials Science and Engineering, B 2011; 176: 283-288.
Fisher, C. A., Jennings, M. R., Bryant, A. T., Pérez-Tomás, A., Gammon, P. M., Brosselard, P., Mawby, P. A. (2012). Physical modelling of 4H-SiC PiN diodes. Paper presented at the Materials Science Forum.
Frazzetto, A., Giannazzo, F., Nigro, R. L., Raineri, V., & Roccaforte, F. (2011). Structural and transport properties in alloyed Ti/Al Ohmic contacts formed on p-type Al-implanted 4H-SiC annealed at high temperature. Journal of Physics D: Applied Physics, 44(25), 255302.
Gao, M., Tsukimoto, S., Goss, S., Tumakha, S., Onishi, T., Murakami, M., & Brillson, L. (2007). Role of interface layers and localized states in TiAl-based ohmic contacts to p-type 4H-SiC. Journal of electronic materials, 36(4), 277-284.
Ghandi, R., Buono, B., Domeij, M., Esteve, R., Schöner, A., Han, J., Ostling, M. (2011). Surface-passivation effects on the performance of 4H-SiC BJTs. Electron Devices, IEEE Transactions on, 58(1), 259-265.
Iucolano, F., Roccaforte, F., Giannazzo, F., Alberti, A., & Raineri, V. (2007). Current transport in Ti/Al/Ni/Au ohmic contacts to GaN and AlGaN. Paper presented at the Materials science forum.
Ivanovskii, A. L., & Enyashin, A. N. (2013). Graphene-like nano-carbides and nano-nitrides of transition metals. Uspekhi Khimii, 82(8), 735-746.
Jennings, M., Fisher, C., Thomas, S., Sharma, Y., Walker, D., Sanchez, A., Burrows, S. (2014). Physical and Electrical Characterisation of 3C-SiC and 4H-SiC for Power Semiconductor Device Applications Physics of Semiconductor Devices (pp. 929-932): Springer.
Jennings, M., Pérez-Tomás, A., Davies, M., Walker, D., Zhu, L., Losee, P., Covington, J. A. (2007). Analysis of Al/Ti, Al/Ni multiple and triple layer contacts to p-type 4H-SiC. Solid-state electronics, 51(5), 797-801.
Johnson, B. J., & Capano, M. A. (2004). Mechanism of ohmic behavior of Al/Ti contacts to p-type 4H-SiC after annealing. Journal of applied physics, 95(10), 5616-5620.
Lanni, L., Ghandi, R., Malm, B. G., Zetterling, C.-M., & Ostling, M. (2012). Design and characterization of high-temperature ECL-based bipolar integrated circuits in 4H-SiC. Electron Devices, IEEE Transactions on, 59(4), 1076-1083.
Miyazawa, T., & Tsuchida, H. (2013). Point defect reduction and carrier lifetime improvement of Si-and C-face 4H-SiC epilayers. Journal of applied physics, 113(8), 083714.
Okamoto, D., Tanaka, Y., Matsumoto, N., Mizukami, M., Ota, C., Takao, K., Okumura, H. (2013). Development of High-Voltage 4H-SiC PiN Diodes on 4° and 8° Off-Axis Substrates. Paper presented at the Materials Science Forum.
Roccaforte, F., Frazzetto, A., Greco, G., Giannazzo, F., Fiorenza, P., Nigro, R. L., Raineri, V. (2012). Critical issues for interfaces to p-type SiC and GaN in power devices. Applied Surface Science, 258(21), 8324-8333.
Sharma, Y., Xu, Y., Jennings, M., Fisher, C., Mawby, P., Feldman, L., & Williams, J. (2014). Improved Stability of 4H Sic-MOS Devices after Phosphorous Passivation with Etching Process. International Journal of Fundamental Physical Sciences, 4(2).
Wang, Z., Saito, M., Tsukimoto, S., & Ikuhara, Y. (2012). Terraces at ohmic contact in SiC electronics: Structure and electronic states. Journal of applied physics, 111(11), 113717.
Yu, A. (1970). Electron tunneling and contact resistance of metal-silicon contact barriers. Solid-state electronics, 13(2), 239-247.
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