TEM studies of multilayer ohmic contacts to n-type AlGaN/GaN

Fay, Mike W.; Moldovan, Grigore; Harrison, Ian; Balmer, R.S.; Soley, D.E.J.; Hilton, K.P.; Hughes, B.T.; Uren, M.J.; Martin, T.; Brown, Paul D.

Abstract

Ti and Pd barrier layers between the Al/Ti diffusion couple and the Au capping layer of multilayer ohmic contacts to n-type AlGaN/GaN field effect transistors were found to be ineffective in preventing the diffusion of Au to the AlGaN following high temperature rapid thermal annealing. The formation of a band of TiN grains at the contact/AlGaN interface is responsible for the activation of the contact. The presence of interfacial Au and threading dislocations are implicated in the formation of additional Ti-nitride inclusions into the AlGaN, although these do not appear to disrupt the Ti-nitride layer at the original contact/nitride interface, nor significantly influence the contact resistance.

Citation

Fay, M. W., Moldovan, G., Harrison, I., Balmer, R., Soley, D., Hilton, K., Hughes, B., Uren, M., Martin, T., & Brown, P. D. TEM studies of multilayer ohmic contacts to n-type AlGaN/GaN. In A. Cullis, & P. Midgely (Eds.), Microscopy of semiconducting materials 2003: proceedings of the Institute of Physics conference, Cambridge University, 31 March - 3 April. IOP Publishing Ltd

• Deposit Date: May 19, 2011
• Peer Reviewed: Peer Reviewed
• Issue: 180
• Series Title: Institute of Physics conference series
• Book Title: Microscopy of semiconducting materials 2003: proceedings of the Institute of Physics conference, Cambridge University, 31 March - 3 April
• ISBN: 9780750309790
• Keywords: TEM, ohmic contact, AlGaN/GaN, field effect transistor
• Public URL: https://nottingham-repository.worktribe.com/output/1022360
• Related Public URLs: http://iopscience.iop.org/