Raman Spectroscopy Characterization of Ion Implanted 4H-SiC

Abstract:

Raman spectroscopy and sheet resistance measurements were used to study the preparation processes of low-resistance p-type 4H-SiC by Al ion implantation with ion doses of 2.45×10¹² - 9.0×10¹⁴ cm^-2 and annealing treatment with temperatures of 1700 - 1900 °C. Greatly different from the LOPC (longitudinal optical phonon-plasmon coupled) Raman mode found from the sample of doping 4H-SiC during epitaxial growth, no significant influence on the surface concentration could be found for the longitudinal optical (LO) mode of Al-implanted 4H-SiC samples. When the Al surface concentration is larger than around 10¹⁸ cm^-3, it was found that the intensity of the LO+ Raman peak (~ 980 - 1000 cm^-1) increases and its full width at half maximum (FWHM) drops with the increase of surface concentration after annealing treatment. Moreover, for surface concentrations above 10¹⁸ cm^-3, the LO+ Raman peak showed a left shift towards the LO peak, which could be related to the increase of free carrier concentration in the Al-implanted 4H-SiC samples. After higher annealing temperatures of 1800 °C and 1900 °C, the crystallinity of Al-implanted 4H-SiC was found to be improved compared to annealing at 1700 °C for surface concentrations larger than 10¹⁸ cm^-3, which is consistent with the results of sheet resistance measurements.

• Periodical: Materials Science Forum (Volume 963)
• Pages: 424-428
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.963.424
• Online since: July 2019
• Authors: Zong Wei Xu*, Y. Song, Mathias Rommel, T. Liu, Matthias Kocher, Z.D. He, H. Wang, B.T. Yao, L. Liu, Feng Zhou Fang
• Keywords: 4H-SiC, Ion Implantation, p-Type Semiconductor, Raman Spectroscopy

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