| 1. |
- Buyanova, Irina A, et al.
(författare)
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Effect of high-temperature electron irradiation on the formation of radiative defects in silicon
- 1999
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 274, s. 528-531
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Tidskriftsartikel (refereegranskat)abstract
- Defect formation processes in silicon caused by electron irradiation performed at elevated temperatures are studied in detail using photoluminescence (PL) spectroscopy. The use of high temperature during electron irradiation has been found to affect considerably the defect formation process, In particular, several new unknown excitonic PL lines were discovered in carbon-rich Si wafers subjected to electron irradiation at temperatures higher than 450 degrees C, The dominant new luminescent center gives rise to a bound exciton PL emission at 0.961 eV. The center is shown to be efficiently created by electron irradiation at temperatures from 450 degrees C up to 600 degrees C. The electronic structure of the 0.961 eV PL center can be described as a pseudodonor case, where the hole is strongly bound at a level 187 meV above the valence band, while the electron is a effective-mass-like particle weakly bound by approximate to 21 meV in the BE state, (C) 1999 Elsevier Science B.V. All rights reserved.
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| 2. |
- Khirunenko, L, et al.
(författare)
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Interstitial carbon related defects in low-temperature irradiated Si: FTIR and DLTS studies
- 2005
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Ingår i: Solid State Phenomena. - 1012-0394. ; 108-109, s. 261-266
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of radiation-induced carbon-related defects in low temperature irradiated oxygen containing silicon has been studied by means of Fourier transform infrared absorption spectroscopy (FTIR) and deep level transient spectroscopy (DLTS). FTIR measurements have shown that annealing of interstitial carbon atom C-i, occurring in the temperature interval 260-300 K, results in a gradual appearance of a number of new absorption bands along with the well known bands related to the CiOi complex. The new bands are positioned at 812, 910.2, 942.6, 967.4 and 1086 cm(-1). It has been found that the pair of bands at 910 and 942 cm(-1) as well as another set of the bands at 812, 967.4 and 1086 cm(-1) display identical behavior upon isochronal annealing, i.e. the bands in both groups appear and disappear simultaneously. The disappearance of the first group occurs at T = 285-300 K while the second group anneals out at T = 310-340 K. These processes are accompanied by an increase in intensity of the bands related to CiOi. It is suggested that intermediate states (precursors) are formed upon the transformation from a single (isolated) Ci atom to a stable CiOi defect. The results obtained in DLTS studies are in agreement with the FTIR data and show unambiguously the formation of CiOi precursors with slightly lower activation energy for the hole emission as compare to that for the main CiOi state.
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| 3. |
- Lindstrom, JL, et al.
(författare)
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Vibrational absorption from vacancy-oxygen-related complexes (VO, V2O, VO2) in irradiated silicon
- 1999
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 274, s. 291-295
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Tidskriftsartikel (refereegranskat)abstract
- Infrared absorption from oxygen-related defects in Si crystals irradiated with electrons (2.5 MeV) at room temperature (RT) and in the range 300-600 degrees C has been investigated. Two new vibrational bands positioned at 10 K at about 1370 and 1430 cm(-1) were observed in samples irradiated at RT. A good correlation is found between these lines and the bands at 836 and 885 cm(-1) known to originate from asymmetrical stretching vibrations (B-1 mode) of an oxygen atom in the neutral and negative VO complex. An attribution of the 1370 and 1430 cm(-1) bands to a combination of the B-1 mode with the symmetrical stretching A(1) mode (weakly IR active) for different charge states of VO is argued to be the most probable. A band at 833.4 cm(-1) is found to increase in strength upon annihilation of divacancies at 250-300 degrees C. The V2O complex is suggested to give rise to this band. New experimental data confirming an attribution of the 895 cm(-1) band to the VO2 complex are presented as well. (C) 1999 Elsevier Science B.V. All rights reserved.
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| 4. |
- Lindström, Lennart, et al.
(författare)
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Carbon-oxygen-related complexes in irradiated and heat-treated silicon : IR absorption studies
- 2002
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Ingår i: Solid State Phenomena. - 1012-0394 .- 1662-9779. ; 82-84, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-oxygen-related complexes in Si crystals enriched with either oxygen (O-16,O-18) or carbon (C-12, C-13) isotopes were investigated by Fourier Transform infrared absorption spectroscopy. The samples were irradiated with electrons at room temperature as well as at elevated temperatures (400-600 degreesC). The oxygen isotopic shifts of the local vibrational modes related to C3 and C4 centers were determined. Several new lines were found to appear after irradiation at elevated temperatures. Possible assignments of them are suggested.
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| 5. |
- Litvinov, VV, et al.
(författare)
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Local vibrational modes of the oxygen-vacancy complex in germanium
- 2002
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Ingår i: Semiconductors. - : Pleiades Publishing Ltd. - 1063-7826 .- 1090-6479. ; 36:6, s. 621-624
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Tidskriftsartikel (refereegranskat)abstract
- Infrared absorption of n- and p-Ge crystals enriched with O-16 and/or O-18 isotopes was studied after irradiation with 6-MeV electrons. Absorption spectra were measured at 10 and 300 K. Along with known bands characteristic of oxygen-containing defects, new lines at 669, 944, and 990 cm(-1) were detected. These bands are annealed at temperatures of 120-140degreesC; the band at 621 cm(-1), previously related to the vacancy-oxygen complex in Ge, is simultaneously annealed. The bands at 621 and 669 cm(-1) showed identical temperatures (10 --> 300 K) and oxygen isotope (O-16 --> O-18) shifts. These bands were found to correspond to various charge states of a defect with an energy level near E-v = 0.25 +/- 0.03 eV. It is assumed that such a defect is the vacancy-oxygen complex (A center). The weak bands at 944 and 990 cm(-1) were identified as combinations of asymmetric stretching modes at 621 and 669 cm(-1) with a symmetric one at 320 cm(-1) for neutral and negative charge states of the A center, respectively.
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| 6. |
- Litvinov, VV, et al.
(författare)
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Vibrational modes of oxygen dimers in germanium
- 2002
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Ingår i: Solid State Phenomena. - 1012-0394. ; 82-84, s. 105-110
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Tidskriftsartikel (refereegranskat)abstract
- Infrared absorption of as-grown, heat-treated and electron irradiated Ge crystals enriched with either O-16 or O-18 oxygen isotopes has been studied. Vibrational absorption bands at 780, 818 and 857 cm(-1) (741, 776 and 811 cm(-1)) are assigned to di-oxygen complexes (dimers) in Ge: O-16 (O-18). This assignment is based on an analysis of positions and isotopic shifts of the lines as well as on an investigation of dependencies of line intensities on heat-treatment temperature and oxygen content in the crystals. It is argued that there are two configurations of oxygen dimers in Ge, the bands at 780 and 818 cm(-1) being related to one of them and the band at 857 cm(-1) to another. The binding energy of the dimer giving rise to the bands at 780 and 818 cm(-1) is estimated to be about 0.35-0.4 eV.
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| 7. |
- Markevich, VP, et al.
(författare)
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Defect reactions associated with divacancy elimination in silicon
- 2003
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 15:39, s. 2779-2789
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Tidskriftsartikel (refereegranskat)abstract
- Defect reactions associated with the elimination of divacancies (V-2) have been studied in n-type Czochralski (Cz) grown and float-zone (FZ) grown Si crystals by means of conventional deep-level transient spectroscopy and high-resolution Laplace deep-level transient spectroscopy (LDLTS). Divacancies were introduced into the crystals by irradiation with 4 MeV electrons. Temperature ranges of the divacancy disappearance were found to be 225-275 degreesC in Cz Si crystals and 300-350 degreesC in FZ Si crystals upon 30 min isochronal annealing. Simultaneously with the V-2 disappearance in Cz Si crystals a correlated appearance of two electron traps with activation energies for electron emission 0.23 eV {E(0.23)} and 0.47 eV {E(0.47)} was observed. It is argued that the main mechanism of the V-2 disappearance in Cz Si crystals is related to the interaction of mobile divacancies with interstitial oxygen atoms. This interaction results in the formation Of V2O centres, which are responsible for the E(0.23) and E(0.47) traps. Electronic properties of the V2O complex were found to be very similar to those of V-2 but energy levels of the two defects could easily be separated using LDLTS. In FZ Si crystals, a few electron traps appeared simultaneously with the V-2 annihilation. The small concentration of these traps compared with the V-2 concentration before annealing prevented their reliable identification.
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| 8. |
- Markevich, VP, et al.
(författare)
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Electrically active radiation-induced defects in Czochralski-grown Si with low carbon content
- 2005
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 17:22, s. 2331-2340
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Tidskriftsartikel (refereegranskat)abstract
- Electrically active defects induced by electron irradiation in Czochralski (Cz)grown Si crystals with low carbon content (N-C <= 2 x 10(15) cm(-3)) have been studied by means of Hall effect measurements, deep level transient spectroscopy (DLTS) and high-resolution Laplace DLTS (LDLTS). It has been found that in n-type carbon-lean Cz-Si irradiated at room temperature a centre with an acceptor level at E-c - 0.11 eV (E-0.11) is one of the dominant radiation-induced defects. This centre is not observed after irradiation in Cz-Si crystals with NC > 10(16) cm(-3). The E-0.11 trap anneals out in the temperature range 100-130 degrees C with the activation energy 1.35 eV. In p-type Cz-Si crystals with low carbon content and boron (NB 2 x 10(14) cm(-3)) one of the dominant radiation-induced defects has been found to be a bistable centre with an energy level at E-v +0.255 eV (H-0.255). It has been inferred from the analysis of temperature dependences of electron occupancy of this level that it is the E(0/++) level of a defect with negative Hubbard correlation energy (negative U). The activation energy for hole emission from the doubly positively charged state of the H0.255 Centre has been determined as 0.358 eV from LDLTS measurements. It is argued that the E-0.11 and H-0.255 energy levels are related to a complex incorporating an oxygen dimer and Si self-interstitial.
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| 9. |
- Markevich, VP, et al.
(författare)
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Electronic properties and structure of a complex incorporating a self-interstitial and two oxygen atoms in silicon
- 2005
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Ingår i: Solid State Phenomena. - 1012-0394 .- 1662-9779. ; 108-109, s. 273-278
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Tidskriftsartikel (refereegranskat)abstract
- The electronic properties and structure of a complex incorporating a self-interstitial (i) and two oxygen atoms are presented by a combination of deep level transient spectroscopy (DLTS), infrared absorption spectroscopy and ab-initio modeling studies. It is argued that the IO2 complex in Si can exist in four charge states (IO2-, IO20, IO2+, and IO2++). The first and the second donor levels of the IO2 complex show an inverted location order in the gap, leading to a E(0/+ +) occupancy level at E-V + 0.255 eV. Activation energies for hole emission, transformation barriers between different structures, and positions of LVM lines for different configurations and charge states have been determined. These observables were calculated by density-functional calculations, which show that they are accounted for if we consider at least two charge-dependent defect structures.
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| 10. |
- Markevich, VP, et al.
(författare)
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Electronic properties of vacancy-oxygen complex in Ge crystals
- 2002
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 81:10, s. 1821-1823
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Tidskriftsartikel (refereegranskat)abstract
- It is argued that the vacancy-oxygen (VO) complex (A center) in Ge has three charge states: double negative, single negative, and neutral. Corresponding energy levels are located at E-c-0.21 eV (VO--/-) and E-v+0.27 eV (VO-/0). An absorption line at 716 cm(-1) has been assigned to the asymmetrical stretching vibration mode of the doubly negatively charged VO complex. (C) 2002 American Institute of Physics.
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| 11. |
- Markevich, VP, et al.
(författare)
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Stable hydrogen pair trapped at carbon impurities in silicon
- 2003
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Ingår i: Defect and Diffusion Forum. - 1012-0386 .- 1662-9507. ; 221-2, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Local mode spectroscopy and ab initio modeling are used to investigate two trigonal defects found in carbon rich Si into which H had been in-diffused. Isotopic shifts with D and C-13 are reported along with the effect of uniaxial stress. Ab-initio modeling studies suggest that the two defects are two forms of the CH2* complex where one of the two hydrogen atoms lies at an anti-bonding site attached to C or Si respectively. The two structures are nearly degenerate and possess vibrational modes in good agreement with those observed experimentally. The defects are energetically favorable in comparison with separated C-s and H-2 in Si and may represent aggregation sites for hydrogen.
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| 12. |
- Markevich, VP, et al.
(författare)
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Vacancy-oxygen complex in Ge crystals
- 2003
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Ingår i: Physica B: Condensed Matter. - : Elsevier BV. - 0921-4526. ; 340, s. 844-848
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Tidskriftsartikel (refereegranskat)abstract
- Vacancy-oxygen (VO) complexes in Ge crystals have been studied by means of high-resolution infrared absorption and deep-level transient spectroscopy (Laplace DLTS) measurements. It is argued that the VO center in Ge has three charge states: double negative (VO--), single negative (VO-) and neutral (VO0) with the corresponding energy levels at E(- -/-) = E-c-0.21 eV and E(-/0) = E-v + 0.27 eV. Absorption lines at 716, 669 and 621 cm(-1) have been assigned to oxygen-related asymmetric stretching vibrations for the VO--, VO- and VO0 states, respectively. Isotope analogues of these lines were identified in O-18-doped Ge samples and studies of crystals containing mixtures of O-16 and O-18 confirm that the complex contains only one oxygen atom. Laplace DLTS combined with uniaxial stress has been used to obtain information on the symmetry of the VO complex. It was found that the defect in VO-- state has orthorhombic-I symmetry (point group C-2v) as for the case of the VO in Si. (C) 2003 Elsevier B.V. All rights reserved.
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| 13. |
- Murin, LI, et al.
(författare)
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Metastable VO2 complexes in silicon: experimental and theoretical modeling studies
- 2005
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Ingår i: Solid State Phenomena. - 1012-0394. ; 108-109, s. 223-228
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Tidskriftsartikel (refereegranskat)abstract
- We report on a combined experimental and theoretical study of the metastable form of the vacancy-dioxygen defect in Si labeled VO2*. Important new experimental observations are the 2 detection of mixed local vibrational modes of VO*(2) in O-16, O-18 co-doped samples, the determination of the position of LVM bands for the negatively charged defect, and an assignment of an acceptor level at about E-c - 0.05 eV. Defect energetics, electrical levels and LVM frequencies of the VO*(2) complex are also investigated by ab-initio density-functional modeling. We find it to be a bistable defect which accounts well for the experimental data. The metastable form produces an acceptor state at similar to 0.05 eV below E-c, and can be thought of as a VO defect perturbed by interstitial oxygen.
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| 14. |
- Murin, LI, et al.
(författare)
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Spectroscopic observation of the TDD0 in silicon
- 2003
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Ingår i: Physica B: Condensed Matter. - : Elsevier BV. - 0921-4526. ; 340, s. 1046-1050
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Tidskriftsartikel (refereegranskat)abstract
- The electronic transitions of 16 neutral thermal double donors (TDD1-TDD16) and of nine positively charged species (TDD1-TDD9) were observed previously in infrared absorption spectra. An earlier species (TDD0) was detected, however, only in persistent photoconductivity and Hall effect studies. In the present work, lines related to the electronic transitions from the ground to excited states in both neutral and singly ionized charge states of the TDD0 have been identified by infrared absorption and bistability of the defect has been confirmed. (C) 2003 Elsevier B.V. All rights reserved.
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