Carbon incorporation into Si at high concentrations by ion implantation and solid phase epitaxy

Abstract

We have studied the incorporation of heavily supersaturated C into Si using solid-phase epitaxy (SPE) of implanted amorphous layers. The strain in the Si1−xCx/Si heterostructures was measured using rocking curve x-ray diffraction. The microstructure and defect introduction were examined using ion channeling and transmission electron microscopy (TEM). The fraction of C located on substitutional lattice sites in the Si was monitored using Fourier transform infrared absorption spectroscopy and ion channeling at resonance energies. Carbon-depth profiles were monitored by secondary ion mass spectroscopy. The metastable solubility limit for the incorporation of C into Si by SPE was found to be 3.0–7.0×1020 atoms/cm3, which is over three orders of magnitude above the equilibrium solubility at the Si melting point. This limit was determined by the ability to regrow without the introduction of microtwins and stacking faults along {111} planes. We postulate the local bond deformation resulting from the atomic size difference between C and Si leads to the faceting of the amorphous–crystalline interface and allows defect introduction, thus limiting the C supersaturations achieved in Si by SPE. It was also found that the defect density in the regrown alloys could be reduced by higher SPE regrowth temperatures in rapid thermal anneal processing.

Formation of compressively strained Si/Si1−xCx/Si(100) heterostructures using gas-source molecular beam epitaxy

“…Methods to grow Si 1 À x C x alloys using molecular beam epitaxy (MBE)-based techniques [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], chemical vapor deposition (CVD) [11,[24][25][26][27][28][29][30], and solid phase epitaxy (SPE) [27,31,32] have been extensively studied. However, most of the previous studies were focused on pseudomorphic growths on Si substrate, and there have been only a limited number of investigations on the strain relaxation process during the heteroepitaxial growths of Si 1 À x C x crystalline films [15,22,23].…”

Defective Solid-Phase Epitaxial Growth of Si

“…Thus, once growth interface motion stops, further annealing allows crystallization to occur via RNG, which is a much slower process than SPEG for crystallizing an α-Si layer. Thus, with further annealing, the remaining α-Si layer will be polycrystalline in nature, rather than single crystal as was previously reported (Rudawski et al, 2009c;Strane et al, 1996).…”

Stimulated emission and emission efficiency enhancement in nanopatterned silicon

“…Substitutional carbon concentrations of up to 7 × 10 20 /cm 3 were achieved using this method. 24 As re-growth progresses, the interface between crystalline and amorphous silicon moves; it is at this interface that carbon atoms are incorporated into the lattice in substitutional sites. In this work, p-type SOI (250nm Si on 3mm BOX, 20 Ωcm, commercially available from Soitech) was used.…”