Characterization of Ti/Al Ohmic Contacts to p-Type 4H-SiC Using Cathodoluminescence and Auger Electron Spectroscopies


Article Preview

We have used depth-resolved cathodoluminescence and Auger electron spectroscopies, DRCLS and AES, respectively, to probe the electronic structure and the composition of Ti/Al ohmic contacts to p-type SiC on a nanometer scale. A continuous Ti-Si-C compound layer was observed using the Auger depth profile. No interfacial Al segregation was found. The secondary electron threshold technique showed a continuous decrease in work function from the p-type SiC to the Ti-Si-C compound layer. Our results support an ohmic contact mechanism by an intermediate semiconductor layer which reduces the otherwise large interfacial Schottky barrier height. DRCLS revealed a ~2.78 eV sub-band gap transition enhanced by interfacial reaction in the near-interface SiC, suggesting the formation of additional C or Si vacancies.



Materials Science Forum (Volumes 527-529)

Edited by:

Robert P. Devaty, David J. Larkin and Stephen E. Saddow




M. Gao et al., "Characterization of Ti/Al Ohmic Contacts to p-Type 4H-SiC Using Cathodoluminescence and Auger Electron Spectroscopies", Materials Science Forum, Vols. 527-529, pp. 891-894, 2006

Online since:

October 2006




[1] S. Tsukimoto, K. Nitta, T. Sakai, M. Moriyama and M. Murakami: J. Electr. Mater. Vol. 33 (2004), p.460.

[2] S. Tanimoto, N. Kritani, M. Hoshi and H. Okushi: Mater. Sci. Forum Vol. 389-393 (2002), p.879.

[3] B.J. Johnson and M.A. Capano: J. Appl. Phys. Vol. 95 (2004), p.5616.

[4] Y. Sakai, M. Kudo and C. Nielsen: J. Vac. Sci. Technol. A Vol. 19 (2001), p.1139.

[5] M. Melloch and J. Cooper: MRS Bull. Vol. 22 (1997), p.42.

[6] N.T. Son, B. Magnusson and E. Janzén: Appl. Phys. Lett. Vol. 81 (2002), p.3945.

[7] F. La Via, F. Roccaforte, V. Raineri, M. Mauceri, A. Ruggiero, P. Musumeci, L. Calcagno, A. Castaldini and A. Cavallini: Microelectronic Engineering: Vol. 70 (2003), p.519.


[8] T. Wimbauer, B.K. Meyer, A. Hofstaetter, A. Scharmann and H. Overhof: Phys. Rev. B Vol. 56 (1997), p.7384.

[9] S.Y. Han, K.H. Kim, J.K. Kim, H.W. Jang, K.H. Lee, N.K. Kim, E.D. Kim and J.L. Lee: Appl. Phys. Lett. Vol. 79 (2001).