Non-equilibrium thermal processing for hyperdoping Si

Hyperdoping has recently emerged as a potential powerful technique to explore new functionalities of semiconductor materials with unique electrical and optical properties [1-3]. Hyperdoping facilitates to introduce dopants into a semiconductor material at concentrations far above those obtained at equilibrium conditions, viz. doping far beyond the solubility limit. Hyperdoped Si with chalcogens or transition metals like Au or Ti has been postulated to be a promising material for many applications, especially for Si-based infrared photodetectors and intermediate band solar cells [2, 3].
In this work, we report on a groundbreaking approach, for hyperdoping Si with Se, consisting of ion implantation followed by millisecond-range flash lamp annealing. This method allows for a solid-phase epitaxy that has been reported to be superior to liquid-phase epitaxy induced during conventional pulsed laser annealing [1]. The resulting Se-hyperdoped Si material is single-phase single crystal with high electrical activation, without surface segregation of Se atoms and with an optically flat surface. We also present a significant room-temperature sub-band gap photoresponse exhibited by Se-hyperdoped Si p-n photodiodes that have been fabricated by this novel approach.
[1] S. Zhou, F. Liu, S. Prucnal, K. Gao, M. Khalid, C. Baehtz, M. Posselt, W. Skorupa, and M. Helm, Sci. Rep. 5, 8329 (2015).
[2] M. J. Sher & E. Mazur, App. Phys. Lett. 105, 032103 (2014).
[3] E. Ertekin, M. T. Winkler, D. Recht, A. J. Said, M. J. Aziz, T. Buonassisi, and J. C. Grossman, Phys. Rev. Lett. 108, 026401 (2012).