Effects of Implantation Temperature on Sheet and Contact Resistance of Heavily Al Implanted 4H-SiC

Abstract:

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Effects of implantation temperature on electrical properties of heavily-Al-doped 4H-SiC layer formed with Al implantation have been investigated. To form the p++ 4H-SiC with the original 4H-stacking structure, the implantation temperature above 175 °C is needed. A decrease in the implantation temperature below 250 °C leads to an increase in the NA-ND. It is suggested that an increase in the density of vacancies with a decrease in the implantation temperature promotes the Al substitution to lattice sites during activation annealing. The lower-temperature implantation also causes a decrease in activation energy for the p-type electrical conduction and a decrease in p-type ohmic contact resistivity. We presume that the increase in the Al acceptors at low-implantation temperatures gives expansion of the impurity bands and formation of valence band tail-states, causing the decrease in the impurity binding energy. The properties obtained with the lower-temperature implantation are desirable for practical applications especially at low temperatures.

Info:

Periodical:

Materials Science Forum (Volumes 645-648)

Edited by:

Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller

Pages:

705-708

DOI:

10.4028/www.scientific.net/MSF.645-648.705

Citation:

T. Watanabe et al., "Effects of Implantation Temperature on Sheet and Contact Resistance of Heavily Al Implanted 4H-SiC", Materials Science Forum, Vols. 645-648, pp. 705-708, 2010

Online since:

April 2010

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$35.00

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