Correlation between crystallinity and mid-infrared optical absorption spectra of silicon supersaturated with sulfur. Issue 1738 (19th March 2015)

• Record Type: Journal Article
• Authors: Umezu, Ikurou; Nagao, Katsuki; Nakai, Tatsuya; Naito, Muneyuki; Inada, Mitsuru; Saitoh, Tadashi; Aoki, Tamao; Sugimura, Akira
• Editors: Li, Y.; Mathur, S.; Zheng, G.
• Is Part Of: MRS proceedings. Issue 1738:(2015)
• Publication Date: 2015-03-19
• Subjects: laser annealing, -- optical properties, -- Si; Electrical engineering -- Congresses; Physics -- Congresses; Materials -- Research -- Congresses; Materials science -- Congresses; 620.11
• DOI: 10.1557/opl.2015.278
• Languages: English
• ISSNs: 0272-9172

Abstract

ABSTRACT: We prepared silicon hyperdoped with sulfur by ion-implantation followed by pulsed laser melting. Effects of laser fluence during pulsed laser melting and of post-annealing on the silicon hyperdoped with sulfur are investigated. The structure of hyperdoped layer changes from poly-to mono-crystal with increasing laser fluence. Interface between sulfur-implanted-layer and single-crystal substrate disappear above 1.1 J/cm 2 . The spectral intensity of mid-infrared (MIR) optical absorption increases with crystallinity and spectral shape depends on whether the melt depth during pulsed laser melting reaches interface between implanted layer and single-crystal silicon substrate or not. The MIR absorption intensity rapidly decreases with thermal annealing temperature and almost disappears at 750 °C. The activation energy of conductivity decreases with increasing laser fluence and further decreases with increasing post thermal-annealing temperature. The insulator-metal transition is observed for the sample annealed at 750 °C. These results indicate that there is no direct correlation between MIR optical absorption band and insulator-metal transition.