SiC nanodot formation in amorphous-Si and poly-Si substrates using a hot-C⁺-ion implantation technique

Abstract

We experimentally studied SiC nanodot formation in an amorphous-Si (a-Si) and poly-Si on quartz substrates, using a hot-C+-ion implantation technique and post-N2 annealing, compared with SiC-dots in a (100) crystal-Si (c-Si) on insulator substrate. Even in the poor crystal quality substrates of the C+-ion implanted in a-Si and poly-Si layers, we experimentally verified 3C-SiC dot formation by transmission electron microscopy, and the strong photoluminescence (PL) intensity in the near-UV-vis regions, because a-Si is partially poly-crystallized by the high-temperature processes of hot-C+-ion implantation and post-N2 annealing. The PL spectral line shape strongly depends on the Si crystal structures, but the peak PL intensity after N2 annealing is almost independent of the Si crystal structures. Moreover, the PL spectrum can be explained by the sum of PL emissions from different cubic and hexagonal polytypes of SiC. We clarified that the three Si crystal structures have a different contribution ratio of PL components of SiC polytypes.

Group-IV-semiconductor quantum-dots in thermal SiO2 layer fabricated by hot-ion implantation technique: different wavelength photon emissions

“…6(a-1), 6(b-1), and 6(c-1), respectively. As a result, it was found that SiC-QDs also consist of 3C-and H-SiC polytypes, although it has already been confirmed 16,19,21) that SiC-dots in the Si layer consist of 3C-and H-SiC polytypes. In contrast, the lattice distance of the C-atoms in Fig.…”

“…Using the self-clustering effects of C atoms in a Si layer via hot-C + ion implantation into Si, which was evaluated by atom probe tomography (ATP), [14][15][16] SiC nano-dots (dot-diameter Φ ≈ 2 nm) can be easily formed in various Si crystal structures from amorphous (a-Si) to crystal Si (c-Si) by a hot-C + -ion implantation technique performed in the wide ranges of Si-substrate temperature T and C + ion-dose D C , that is, 500 ⩽ T ⩽ 1000 °C and 5 × 10 12 ⩽ D C ⩽ 7 × 10 16 cm −2 , [16][17][18][19][20][21] to evaluate the quantum mechanical phenomena in SiC-dots as well as to realize Si-based photonic devices. [22][23][24] The selfclustering effects of ion-implanted C atoms in Si leads to the local condensation of C-atoms with the diameter of several nm in Si layer, resulting in the local formation of SiC nano-dots in Si layers.…”

“…[22][23][24] The selfclustering effects of ion-implanted C atoms in Si leads to the local condensation of C-atoms with the diameter of several nm in Si layer, resulting in the local formation of SiC nano-dots in Si layers. 16,19,21) The hot-C + -ion implantation process can reduce the ion-implantation-induced damage to the Si layer, which is one of the advantageous characteristics of the hot-C + -ion implantation process. 18) Moreover, the partial formation of SiC-polytypes with different E GX values for cubic-(3C-SiC) and hexagonal-SiC (H-SiC) nano-dots were also confirmed both at the oxide/Si interface and in the Si layer, using corrector-spherical aberration transmission electron microscopy (CSTEM), high-angle annular-dark-field (HAADF) scanning transmission electron microscopy (STEM), and electron diffraction (ED) patterns that were obtained by fast Fourier transform (FFT) analysis of the lattice spots of CSTEM data.…”

Physical mechanism for photon emissions from group-IV-semiconductor quantum-dots in quartz-glass and thermal-oxide layers

“…Recently, for realizing Si-based photonics, [1][2][3] we have been experimentally studied photon emissions from nano-structures of group-IV semiconductors (Si, SiC, and C), such as two-dimensional (2D) Si, 4,5) SiC-nano-dots in various crystal structures of Si [6][7][8][9][10][11] [amorphous-Si (a-Si), poly-Si, crystal-Si (c-Si)], and group-IV semiconductor quantum-dots (IV-QD) of Si, SiC, and C in thermal Si-oxide (OX). 12,13) Si-, SiC-, and C-dots were fabricated by very simple hot-ion implantations of single Si + , double Si + /C + , and single C + , respectively, and a post N 2 annealing was carried out to improve the dot quality.…”

“…13) The dots had diameter Φ of approximately 2-4 nm and surface density N of approximately 2 × 10 12 cm −2 . 8,9,[11][12][13] Photoluminescence (PL) intensity (I PL ) of SiC-dots in Si was two orders of magnitude larger than that of 2D-Si. 8) In addition, we demonstrated that the PL emission coefficient η of SiC-QD in OX was approximately 2.5 times larger than that of SiC-dots in Si, because of quantum confinement effects of electrons in SiC-QD.…”