Ion-Beam-Induced Epitaxy and Solid Phase Epitaxy of Sigec on Si Formed by Ge and C Ion Implantation and their Structural
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Electrotechnical Laboratory, 1-1-4 Umezono, Tsukuba, Ibaraki 305 Japan Meiji University, 1-1-1 Higashimita, Tama, Kawasaki, Kanagawa 214, Japan National Institute for Research in Inorganic Materials, 1-1 Namiki, Tsukuba, Ibaraki 305 Japan
ABSTRACT Epitaxial layers of Sil-x-yGexCy on Si(100) (x=0.13 and y=0.014 at peak concentration) were formed by ion implantation of Ge ions and C ions at room temperature (RT) and by subsequent IBIEC (ion-beam-induced epitaxial crystallization) process with 400keV Ge and Ar ions at 300-400'C and SPEG (solid phase epitaxial growth) process up to 840'C. Crystallization up to the surface both by IBIEC and SPEG processes has been confirmed with RBS-channeling analysis. X-ray diffraction experiments have demonstrated strain compensation by incorporation of C atoms for IBIEC-grown Sil-x-yGexCy/Si samples, whereas strain accommodation due to C precipitation has been observed for SPEG-grown Silx-yGexCy/Si samples. Photoluminescence (PL) observed at 2K from IBIEC-grown samples has shown intense I1 peak with/without I1 related (Ar) peak and that from SPEG-grown samples has shown G line emission. These optical properties could suggest that small vacancy agglomeration is dominant in IBIEC-grown samples and C agglomeration is dominant in SPEG-grown samples, respectively. INTRODUCTION SiGeC on Si has recently attracted interest because of the structural advantage in strain compensation and of bandgap modification by C atom incorporation in SiGe [1-3]. The optical properties, however, have not been well understood so far for SiGeC on Si. Gupta et al. have investigated donor complex formation in high-dose Ge implanted Si with and without C implantation [4]. Boucaud et al. have reported the band-edge luminescence at 77K from Sil-xyGexCy alloys formed by the rapid thermal chemical vapor deposition [5]. On the other hand, ion-beam-induced epitaxial crystallization (IBIEC) in semiconductors has an attractive feature that it induces crystallization at lower temperatures than in the process of solid phase epitaxial growth (SPEG) [6-8]. Moreover, IBIEC can provide non-thermal equilibrium incorporation of foreign atoms far in excess of the solubility limit. C is known to be highly insoluble in Si and C precipitation is reported to be a severe problem for SiGeC in the SPEG process [9]. Comparison of IBIEC process to SPEG process in Si i-x-yGexCy/Si growth is, therefore, an investigation of interest from the material synthesis point of view. In this paper we present the structural and optical properties of Sil-xy GexCy layers on Si(100) formed by high-dose Ge and C ion implantation and subsequently grown both by IBIEC and SPEG processes. Since part of the structural properties for IBIEC growth for Si I-xyGexCy/Si has been already reported elsewhere [10], optical properties that are relevant to structural properties are focused in the following. EXPERIMENTAL Non-doped (100)-oriented Si wafers (float-zone, p> 0.1 i2cm) were implanted at room temperature with 80keV 74Ge ions to 1016 cm- 2 with a current densi
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