Passivation of shallow impurities in Si by annealing in H2 at high temperature

Veloarisoa, I. A.; Stavola, Michael; Kozuch, D. M.; Peale, R. E.; Watkins, G. D.

doi:10.1063/1.106099

Cited by 48 publications

(20 citation statements)

References 12 publications

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“…Hydrogen or deuterium was introduced by heating the samples at 1250°C for 1 h in sealed ampoules that contained H 2 or D 2 at a pressure of 2 3 atm at room temperature. [36][37][38] Following the anneal, the samples were quenched to room temperature in ethylene glycol. By this procedure it was possible to generate absorption bands for the Al-H and Al-D complexes which were stronger and sharper than those used in previous studies in which the samples had been implanted with Al and passivated in a hydrogen plasma.…”

Section: Sample Preparation and Experimental Proceduresmentioning

confidence: 99%

Al-H and Al-D complexes in Si: A uniaxial-stress study of the hydrogen vibrational modes

Stavola

Davies

1996

Phys. Rev. B

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Perturbation of the 2201-cm Ϫ1 absorption line of the Al-H complex in Si by uniaxial stress is shown to be consistent with a stretching mode of a center with an effectively trigonal symmetry. Quantitative analyses of the effects of the stresses and of varying the temperature reveal the presence of a very-low-frequency transverse mode which transforms as the E irreducible representation in the trigonal symmetry. Its frequency is 64 cm Ϫ1 in the ground state of the stretching mode ͑representation A 1 ͒. An A 1 ϩE combination mode, observed only under stress, lies 24 cm Ϫ1 above the excited state of the A 1 mode. Upon substituting D for H, the frequencies of the stretching and transverse modes are reduced by approximately a factor of 1/&, as expected for vibrations which predominantly involve the H ͑D͒ atom. The symmetries of the center and of its modes are unchanged by the isotopic substitution. The Al-H axis may be preferentially aligned along one of the ͗111͘ axes by an applied stress. The barrier to reorientation is ϳ370 meV. ͓S0163-1829͑96͒03139-6͔

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Section: Sample Preparation and Experimental Proceduresmentioning

confidence: 99%

Al-H and Al-D complexes in Si: A uniaxial-stress study of the hydrogen vibrational modes

Stavola

Davies

1996

Phys. Rev. B

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“…Assignments of these levels to specific H defects are then made. Models for the defects responsible for the neutralization of the electrical activity of the Au and Ag centers are proposed.[S0031-9007 (99)08596-8] PACS numbers: 71.15.Mb, 61.72.Bb, 71.55.CnThe interaction of hydrogen with transition metals (TM) has recently become of great interest [1][2][3][4]. The presence of hydrogen has three effects on the electronic levels of the TM impurity.…”

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Calculations of Electrical Levels of Deep Centers: Application to Au-H and Ag-H Defects in Silicon

et al. 1999

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First-principles local-density formalism cluster theory is used to determine the structure of Au-and Ag-hydrogen complexes in Si. The theory, with an empirical correction, is then applied to extract their donor and acceptor levels and these are compared with capacitance transient spectroscopic measurements. Assignments of these levels to specific H defects are then made. Models for the defects responsible for the neutralization of the electrical activity of the Au and Ag centers are proposed.[S0031-9007 (99)08596-8] PACS numbers: 71.15.Mb, 61.72.Bb, 71.55.CnThe interaction of hydrogen with transition metals (TM) has recently become of great interest [1][2][3][4]. The presence of hydrogen has three effects on the electronic levels of the TM impurity. It can shift these levels, introduce additional ones, or it can remove them completely from the band gap achieving passivation [1]. However, in no case are these effects completely understood. One problem is that first-principles techniques which can determine the structure of the complex cannot predict the donor (0͞1) and acceptor (2͞0) levels with the required precision. To overcome this some empirical correction is necessary usually to the band gap used in the calculation [5,6]. We find that by employing an empirical correction in a different way, these levels can be calculated to within about 0.2 eV and as such the theory can be used to predict the electrical activity of Au-and Ag-hydrogen defects [7].The donor level with respect to E y is the difference between the ionization energy of the defect and that of bulk Si. If the wave function of the defect is localized within the cluster and does not overlap the surface, then, in principle, the ionization energy of the defect can be calculated by the cluster method. However, as the valence band wave functions are always extended throughout the cluster and affected by the surface, the bulk ionization energy cannot be calculated by the method. To circumvent this problem, we compare the ionization energy of the defect, I d , with that of a standard defect, I s . The position of the donor level, E͑0͞1͒ d , is then given by E͑0͞1͒ d E͑0͞1͒ s 1 I d 2 I s , where the donor level of the standard defect, E͑0͞1͒ s , is taken from experiment. In the same way the electron affinities can be used to determine the acceptor levels. In practice we take the standard defect to be the carbon interstitial, C i , which is known to assume the same structure in all charge states [8]. This has (0͞1) and (2͞0) levels at E y 1 0.28 eV and E c 2 0.1 eV, respectively [9]. The ionization energies and electron affinities are calculated by applying Slater's transition state argument [10,11]. Using the relaxed geometry appropriate to the transition state takes into account, to first order, the difference in structures between the neutral and ionized clusters. This method is remarkably accurate. For example, by comparing the total energies of relaxed neutral and ionized molecules, the ionization energy of the water molecule is found to be 13.37 eV. Th...

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“…The hydrogenation is achieved by the post-deposition anneal of a H-rich SiN x anti-reflection coating [1] and H concentrations of the order of 10 15 cm −3 are achieved [2,3] throughout the bulk of the sample. About one order of magnitude higher concentrations of H are obtained by annealing the sample near the melting point in an H 2 ambient followed by rapid quenching [4]. Cast Si material is C rich.…”

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Huge isotope effect on the vibrational lifetimes of an H2*(C) defect in Si

et al. 2013

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The hydrogenation of C-rich Si leads to the formation of two (almost) energetically degenerate H * 2 (C) complexes, each containing one substitutional C (Cs) and two interstitial H atoms which are located at a bond-centered (bc) and an anti-bonding (ab) site, respectively. The two defects are trigonal: Cs − H bc · · · Si − H ab and H ab − Cs · · · H bc − Si. Fourier-transform infrared (FTIR) absorption spectra of these two defects should show two Cs − H and two Si − H stretch modes, but the H ab − Cs mode was absent in earlier studies. The missing line has now been observed by FTIR in especially C-rich Si material. The line is unexpectedly broad, suggesting a very short vibrational lifetime. Partial D substitutions result in the formation of a H ab − Cs · · · D bc − Si center. In this defect, the H ab − Cs line shifts by only 0.3 cm −1 but becomes very sharp, suggesting a long lifetime. The IR line widths show that the vibrational lifetime of the H ab − Cs mode in H ab − Cs · · · D bc − Si is about 16 times longer than that of the same H ab − Cs mode in H ab − Cs · · · H bc − Si. This paper contains experimental data and first-principles calculations which explain this isotope effect.

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Passivation of shallow impurities in Si by annealing in H2 at high temperature

Cited by 48 publications

References 12 publications

Al-H and Al-D complexes in Si: A uniaxial-stress study of the hydrogen vibrational modes

Al-H and Al-D complexes in Si: A uniaxial-stress study of the hydrogen vibrational modes

Calculations of Electrical Levels of Deep Centers: Application to Au-H and Ag-H Defects in Silicon

Huge isotope effect on the vibrational lifetimes of an H2*(C) defect in Si

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