Formation of hydrogen-boron complexes in boron-doped silicon treated with a high concentration of hydrogen atoms

The formation of hydrogen (H) related complexes and their effect on boron (B) dopant were investigated in B-ion implanted and annealed silicon (Si) substrates treated with a high concentration of H. Isotope shifts by replacement of ${}^{10}\mathrm{B}$ with ${}^{11}\mathrm{B}$ were observed for some H-related Raman peaks, but not for other peaks. This shows proof of the formation of B-H complexes in which H directly bonds to B in Si. This is an experimental result concerning the formation of B-H complexes with H bonded primarily to B. Electrical resistivity measurements showed that the B acceptors are passivated via the formation of the observed B-H complexes, as well as the well-known passivation center in B-doped Si; namely, the H-B passivation center.

Figure 1

Raman spectra observed for (a) Si implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$ and (b) bulk Si, both of which were subjected to hydrogenation at 245 °C. The Raman spectrum shown in (c) was obtained for Si implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$, followed by deuteration at 245 °C.

Figure 2

(a) Raman spectra observed for Si implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions or ${}^{10}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$, followed by hydrogenation at 220 °C. The inset (b) shows a magnification of the peaks related to B-H complexes.

Figure 3

Dependence of the Raman peaks related to B-H complexes on the concentration of B for specimens hydrogenated at two different temperatures: (a) 165 °C and (b) 245 °C. The frequencies of the peaks related to B-H complexes are shadowed.

Figure 4

Dependence of the intensities of H-related Raman peaks on the concentration of B for specimens hydrogenated at two different temperatures: (a) 165 °C and (b) 245 °C.

Figure 5

Raman spectra observed for specimens hydrogenated at different temperatures. The specimens were implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$, followed by hydrogenation at each temperature shown for 30 min. The frequencies of the peaks related to B-H complexes are shadowed.

Figure 6

Dependence of the peak intensities of H-related Raman peaks on the hydrogenation temperature. The specimens were implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$, followed by hydrogenation at each temperature shown for 30 min.

Figure 7

Raman spectra observed for specimens hydrogenated for different durations. The specimens were implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $5\times {10}^{15}{\mathrm{cm}}^{-2}$, followed by hydrogenation at 190 °C. The frequencies of the peaks related to B-H complexes are shadowed.

Figure 8

Dependence of the peak intensities of H-related Raman peaks on the hydrogenation duration. The specimens were implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $5\times {10}^{15}{\mathrm{cm}}^{-2}$, followed by hydrogenation at 190 °C.

Figure 9

Depth profiles of the concentrations of B and H introduced into B-doped Si specimens. The depth profile of B was obtained for a Si specimen implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$ and annealed at 900 °C. The depth profiles of H were then obtained for B-doped Si hydrogenated at 190 °C.

Figure 10

Dependence of the resistivity of hydrogenated B-doped Si specimens and the peak intensity of the H-B passivation center, platelets, and B-H complexes (2283 and $2470{\mathrm{cm}}^{-1}$) on the hydrogenation temperature. The dotted line shows the resistivity before hydrogenation. The specimens were implanted with 30 keV ${}^{11}\mathrm{B}^{+}$ ions at a dose of $1\times {10}^{15}{\mathrm{cm}}^{-2}$. Hydrogenation was performed at each temperature shown for 30 min.

Figure 11

(Color online) Possible model of the B-H complex. In this configuration, the B-H complex is formed via the formation of the H-B passivation center and the subsequent intermediate state. The B-H complex contains three H atoms, one of which bonds to a B atom in the complex.