| 1. |
- Khirunenko, L.I., et al.
(författare)
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Complexes of self-interstitials with oxygen atoms in germanium
- 2008
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Ingår i: Materials Science in Semiconductor Processing. - : Elsevier BV. - 1369-8001 .- 1873-4081. ; 11:5, s. 344-347
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Tidskriftsartikel (refereegranskat)abstract
- Interactions of germanium self-interstitials with interstitial oxygen atoms in Ge crystals have been studied by combining experimental and theoretical methods. Self-interstitials were created in oxygen-rich Ge crystals by irradiation with MeV electrons at 80 K, and I-O-related complexes were studied by means of infrared absorption spectroscopy, while the density functional theory was used to model structures, local vibrational modes and electronic properties of IO and I2O centers. It is argued that two absorption lines at 674 and 602 cm-1, which develop upon annealing of irradiated Ge:O crystals in the temperature range 180-220 K, are related to IO complexes, while another set of bands at 713 and 803 cm-1 is related to I2O. Those assignments are supported by the comparison with the calculated local vibrational modes of the defects.
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| 2. |
- Coutinho, J., et al.
(författare)
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Interstitial carbon-oxygen center and hydrogen related shallow thermal donors in Si
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:1, s. 014109-11
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Tidskriftsartikel (refereegranskat)abstract
- The interstitial carbon-oxygen defect is a prominent defect formed in e-irradiated Cz-Si containing carbon. Previous stress alignment investigations have shown that the oxygen atom weakly perturb the carbon interstitial but the lack of a high-frequency oxygen mode has been taken to imply that the oxygen atom is severely affected and becomes overcoordinated. Local vibrational mode spectroscopy and ab initio modeling are used to investigate the defect. We find new modes whose oxygen isotopic shifts give further evidence for oxygen overcoordination. Moreover, we find that the calculated stress-energy tensor and energy levels are in good agreement with experimental values. The complexes formed by adding both single (CiOiH) and a pair of H atoms (CiOiH2), as well as the addition of a second oxygen atom, are considered theoretically. It is shown that the first is bistable with a shallow donor and deep acceptor level, while the second is passive. The properties of CiOiH and CiO2iH are strikingly similar to the first two members of a family of shallow thermal donors that contain hydrogen.
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| 3. |
- Boisvert, V, et al.
(författare)
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Characterization of oxygen dimer-enriched silicon detectors
- 2005
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 552:1-2, s. 49-55
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Tidskriftsartikel (refereegranskat)abstract
- Various types of silicon material and silicon p(+)n diodes have been treated to increase the concentration of the oxygen dimer (02) defect. This was done by exposing the bulk material and the diodes to 6 MeV electrons at a temperature of about 350 degrees C. FTIR spectroscopy has been performed on the processed material confirming the formation of oxygen dimer defects in Czochralski silicon pieces. We also show results from TSC characterization on processed diodes. Finally, we investigated the influence of the dimer enrichment process on the depletion voltage of silicon diodes and performed 24 GeV/c proton irradiations to study the evolution of the macroscopic diode characteristics as a function of fluence.
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| 4. |
- Buyanova, Irina A., et al.
(författare)
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Photoluminescence characterization of defects created in electron-irradiated silicon at elevated temperatures
- 2000
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Ingår i: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 72:2, s. 146-149
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Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence (PL) spectroscopy is employed to investigate radiative defects created in Si during electron-irradiation at elevated temperatures. The use of high temperature during electron irradiation has been found to affect considerably the defect formation process. The effect critically depends on the temperature of the irradiation as well as doping of the samples. For carbon-lean Si wafers high temperature electron irradiation stimulates the formation of extended defects, such as dislocations and precipitates. For carbon-rich Si wafers the increase of irradiation temperature up to 300°C enhances the formation of the known carbon-related defects. In addition, several new excitonic PL lines were observed after electron irradiation at T = 450°C. The dominant new PL center gives rise to a BE PL emission at 0.961 eV. The electronic structure of the 0.961 eV defect is discussed based on temperature-dependent and magneto-optical studies.
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| 5. |
- Coutinho, Jose, et al.
(författare)
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Electronic and dynamical properties of the silicon trivacancy
- 2012
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 86:17
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Tidskriftsartikel (refereegranskat)abstract
- The trivacancy (V3) in silicon has been recently shown to be a bistable center in the neutral charge state, with a fourfold-coordinated configuration, V3[FFC], lower in energy than the (110) planar one [ V. P. Markevich et al. Phys. Rev. B 80 235207 (2009)]. Transformations of the V3 defect between different configurations, its diffusion, and disappearance upon isochronal and isothermal annealing of electron-irradiated Si:O crystals are reported from joint deep level transient spectroscopy measurements and first-principles density-functional calculations. Activation energies and respective mechanisms for V3 transformation from the (110) planar configuration to the fourfold-coordinated structure have been determined. The annealing studies demonstrate that V3 is mobile in Si at T>200 ∘C and in oxygen-rich material can be trapped by interstitial oxygen atoms so resulting in the appearance of V3O complexes. The calculations suggest that V3 motion takes place via consecutive FFC/planar transformation steps. The activation energy for the long-range diffusion of the V3 center has been derived and agrees with atomic motion barrier from the calculations
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| 6. |
- Coutinho, J., et al.
(författare)
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Over-coordinated oxygen in the interstitial carbon-oxygen complex
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308, s. 305-308
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Tidskriftsartikel (refereegranskat)abstract
- The interstitial carbon-oxygen complex is one of the most prominent defects formed in e-irradiated Cz-Si containing carbon. Stress alignment investigations have shown that the oxygen atom only perturbs the carbon interstitial but the lack of a high frequency oxygen mode has been taken to imply that the oxygen atom is over-coordinated. Local vibrational mode spectroscopy and ab initio modeling are used to investigate the defect. We find new modes whose oxygen isotopic shifts, along with the piezoscopic stress-energy tensor support the trivalent model, thus providing evidence for oxygen over-coordination.
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| 7. |
- Coutinho, J., et al.
(författare)
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Thermal double donors and quantum dots
- 2001
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 87:23, s. 235501-
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Tidskriftsartikel (refereegranskat)abstract
- Combined local mode spectroscopy and ab initio modeling are used to demonstrate for the first time that oxygen atoms in thermal double donors (TDD) in Si are in close proximity. The observed vibrational modes in 16O, 18O, and mixed isotopic samples are consistent with a model involving [110] aligned oxygen chains made up of an insulating core lying between electrically active ends. The model also explains the minute spin density observed on oxygen in TDD+ as well as the piezospectroscopic tensors of the donors. The analogy between the thermal donors and quantum dots is emphasized.
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| 8. |
- Hermansson, J., et al.
(författare)
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Complexes of the self-interstitial with oxygen in irradiated silicon : A new assignment of the 936 cm-1 band
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 302-303, s. 188-192
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Three vibrational infrared absorption bands at about 936, 944 and 956 cm-1 appear commonly in spectra of Czochralski-grown silicon irradiated at low temperatures. All three bands have earlier been assigned to local vibrational modes related to oxygen in the complex of the silicon and the oxygen interstitials (IOi). However, it is shown that such an assignment of the 936 cm-1 band clearly is inconsistent with many facts and observations and that the band is most likely due to oxygen vibrations in the Si interstitial pair and interstitial oxygen complex, I2Oi. © 2001 Published by Elsevier Science B.V.
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| 9. |
- Hourahine, B., et al.
(författare)
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Evidence for H2* trapped by carbon impurities in silicon
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308, s. 197-201
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Tidskriftsartikel (refereegranskat)abstract
- Local mode spectroscopy and ab initio modelling are used to investigate two trigonal defects found in carbon-rich Si into which H had been in-diffused. Isotopic shifts with D and 13C are reported along with the effect of uniaxial stress. Ab initio modelling 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.
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| 10. |
- Lindstrom, J.L., et al.
(författare)
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Defect engineering in Czochralski silicon by electron irradiation at different temperatures
- 2002
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 186:1-4, s. 121-125
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Tidskriftsartikel (refereegranskat)abstract
- Infrared absorption studies of defect formation in Czochralski silicon irradiated with fast electrons in a wide range of temperatures (80-900 K) have been performed. The samples with different contents of oxygen (16O,18O) and carbon (12C,13C) isotopes were investigated. The main defect reactions are found to depend strongly on irradiation temperature and dose, as well as on impurity content and pre-history of the samples. Some new radiation-induced defects are revealed after irradiation at elevated temperatures as well as after a two-step (hot+room-temperature (RT)) irradiation. © 2002 Elsevier Science B.V. All rights reserved.
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| 11. |
- Lindstrom, J.L., et al.
(författare)
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Interaction between self-interstitials and the oxygen dimer in silicon
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308-310, s. 284-289
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Tidskriftsartikel (refereegranskat)abstract
- Interactions between the oxygen dimer (O2i) and silicon self-interstitials (I) and vacancies (V) have been studied in Czochralski-grown silicon (Cz-Si) crystals using infrared absorption and deep level transient spectroscopies. The focus in this report is on reactions of O2i with I. The first step in this interaction is found to be the formation of a self-interstitial-dioxygen centre (IO2i) with oxygen-related local vibrational mode (LVM) bands at 922 and 1037 cm-1. During the second formation step, another centre, I2O2i, with LVM bands at 918 and 1034 cm-1 is suggested to appear. A Si-related band at about 545 cm-1 is also assigned to both the IO2i and I2O2i centres. The IO2i centre is found to be electrically active with an acceptor level at Ec - 0.11 eV. The both defects, IO2i and I2O2i, are stable at room temperature and anneal out at about 400 and 550 K, respectively. © 2001 Elsevier Science B.V. All rights reserved.
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| 12. |
- Lindström, Lennart, et al.
(författare)
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The VO2* defect in silicon
- 2003
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Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 340-342, s. 509-513
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The vacancy-dioxygen complex (VO2) is one of the main defects formed in irradiated Cz-Si crystals upon annealing (or irradiation) in the temperature range 300-400°C. In this defect two oxygen atoms share a vacancy, each bonded to two silicon neighbors. Independent vibrations of these O atoms give rise to one infrared absorption band at 895.5 cm-1 at 10 K. We report on an experimentally discovered bistability of this defect. We suggest an alternative configuration, VO2*, where only one O atom is inside the vacancy while the second O atom is in a backbond position. Two vibrational bands, at 928.4 and 1003.8 cm-1 (positions at 15 K), are assigned to this configuration. © 2003 Elsevier B.V. All rights reserved.
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| 13. |
- Litvinov, V V, et al.
(författare)
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Calibration factor for determination of interstitial oxygen concentration in germanium by infrared absorption
- 2005
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Ingår i: Solid State Phenomena. - 1012-0394. ; 108-109, s. 735-740
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Tidskriftsartikel (refereegranskat)abstract
- Intensities of infrared absorption due to asymmetric stretching vibrations of interstitial oxygen atoms in Ge crystals enriched with O-16 and O-18 isotopes have been compared with oxygen concentrations determined by means of secondary ion mass spectrometry (SIMS). For Ge samples with oxygen content less than 510(17) cm(-3) a good correlation has been found between the values of oxygen concentration and values of absorption coefficient in maximum of the absorption band at 855.6 cm(-1) with a proportionality coefficient C-O = 0.95 10(17) cm(-2). It is argued that kinetics of oxygen-related thermal double donor formation and oxygen loss upon heat-treatments of Ge crystals at 350 degrees C cannot be described properly with the application of calibration coefficient C-O 510(16) cm(-2), which is widely used for the determination of oxygen concentration in Ge crystals.
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| 14. |
- Litvinov, V. V., et al.
(författare)
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Determination of interstitial oxygen concentration in germanium by infrared absorption
- 2006
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 100:3
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Tidskriftsartikel (refereegranskat)abstract
- The intensities of infrared absorption due to the asymmetric stretching vibrations of interstitial oxygen atoms in Ge crystals enriched with O-16 and O-18 isotopes have been compared with oxygen concentrations determined by means of secondary ion mass spectrometry. For Ge samples with oxygen content less than 5 x 10(17) cm(-3), a good correlation has been found between the values of oxygen concentration and the values of the absorption coefficient at the maximum of the O-16(i) related absorption band at 855.6 cm(-1) with a proportionality coefficient C-O = 1.05 x 10(17) cm(-2). (c) 2006 American Institute of Physics.
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| 15. |
- Litvinov, V V, et al.
(författare)
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Oxygen loss and thermal double donor formation in germanium
- 2006
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Ingår i: Materials Science in Semiconductor Processing. - : Elsevier BV. - 1369-8001. ; 9:4-5, s. 619-624
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Tidskriftsartikel (refereegranskat)abstract
- Kinetics of interstitial oxygen loss and oxygen-related thermal double donor (TDD) generation upon heat treatments of Ge:O crystals at 350 degrees C have been studied. The TDD concentration (N-TDD) was derived from Hall effect measurements in the temperature range 77-400 K. The bistability of the first TDD species was taken into account. The interstitial oxygen concentration ([O-i]) in the crystals was determined from measurements of the intensity of the infrared absorption band at 855 cm(-1) at room temperature with the use of a recently obtained calibration coefficient Co = 1.05 x 10(17) cm(-2). From an analysis of the [O-i](t) and N-TDD(t) kinetics a confirmation of recent suggestions about faster diffusivity of small oxygen clusters compared to the diffusivity of single interstitial oxygen atoms was obtained. Average numbers (N) of oxygen atoms lost per TDD species created, N = Delta[O-i]/N-TDD, were calculated at different stages of the TDD generation. The obtained values of N are consistent with those expected in accordance with the recent models of the TDD structure. In particular, an average number of oxygen atoms per TDD species was about 5 at initial stages of the heat treatment when the first members (the TDD2 and TDD3 species) of the TDD family were dominant. N was found to be about 10 after extended anneals at 350 degrees C when the TDD6 and TDD7 species were dominant.
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| 16. |
- Markevich, V.P., et al.
(författare)
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Electronic properties of vacancy-oxygen complexes in SiGe alloys
- 2003
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Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 340, s. 790-4
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Tidskriftsartikel (refereegranskat)abstract
- Capacitance transient techniques, combined with ab initio modeling, were employed to study the electronic properties and structure of vacancy-oxygen (VO) complexes in unstrained Czochralski-grown Si1-xGex crystals (0
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| 17. |
- Markevich, V.P., et al.
(författare)
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Local vibrational mode bands of V-O-H complexes in silicon
- 1999
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 273-274, s. 300-304
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Tidskriftsartikel (refereegranskat)abstract
- H2 molecules, which are introduced into moderately doped silicon crystals by high-temperature in-diffusion from H2 gas ambient followed by fast cooling to room temperature, are found to interact effectively with the defects induced by irradiation of the crystals with fast electrons. In Czochralski-grown silicon crystals, the interaction of the mobile H2 molecules with vacancy-oxygen defects (A centers) leads to the creation of V-O-H2 complexes. This complex gives rise to infrared (IR) absorption lines at 943.5, 2126.4, and 2151.5 cm-1. Ab initio calculations showed that the most stable configuration of V-O-H2 consists of one oxygen and two hydrogen atoms sharing a vacancy site. It is suggested that the interaction of the V-O-H2 complexes with interstitial oxygen atoms results in the formation of V-O2-H2 complexes, which are responsible for the IR absorption line at 891.5 cm-1.
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| 18. |
- Markevich, V. P., et al.
(författare)
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Observation and theory of the V-O-H2 complex in silicon
- 2000
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:19, s. 12964-12969
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of hydrogen with radiation-induced defects (RD's) in Czochralski-grown silicon crystals has been studied by infrared-absorption spectroscopy and ab initio modeling. Hydrogen and/or deuterium was introduced into the crystals by indiffusion from H2 (D2) gas at 1200-1300 °C. The samples were subsequently irradiated with fast electrons (E=2-4 MeV) and annealed in the temperature range of 100-600 °C. The centers produced by the irradiation were the same in both the untreated and treated cases, namely the A-center, Ci-Oi complex, and divacancy. A heat treatment of the H-treated samples resulted in the enhanced loss of these centers and the formation of centers containing hydrogen. The disappearance of the A centers in the temperature range of 100-150 °C is correlated with the appearance of three local vibrational modes (LVM's) at 943.5, 2126.4, and 2151.5 cm-1. The isotopic shifts of these lines were obtained from measurements on the samples doped with hydrogen and deuterium. The lines are identified as related to stretching vibrational modes of a complex that consists of one oxygen and two hydrogen atoms sharing a vacancy site (V-O-H2 complex). Ab initio calculations are used to explore the structures and properties of this defect. The origin of other LVM bands, which were observed upon annealing, is discussed.
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| 19. |
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| 20. |
- Murin, L.I., et al.
(författare)
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Early stages of oxygen clustering in hydrogenated Cz-Si : IR absorption studies
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 302-303, s. 180-187
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The formation kinetics of small oxygen clusters in hydrogenated Si has been studied by means of infrared absorption measurements. Hydrogen was introduced into the crystals by in-diffusion from H2 gas at 1200-1300°C. The samples were heated at temperatures in the range of 280-370°C for different durations. At initial stages of heat-treatment, enormous generation rates of the oxygen dimer have been observed in hydrogenated samples. This indicates highly enhanced diffusion of the interstitial oxygen atoms. The maximum achievable concentration of the dimers is found to be limited by their dissociation rate even at temperatures of about 300°C, while in as-grown crystals the capture processes are known to be dominant in this temperature region. An explanation of this phenomenon is presented. © 2001 Published by Elsevier Science B.V.
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| 21. |
- Murin, L.I., et al.
(författare)
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Isotopic effects on vibrational modes of thermal double donors in Si and Ge
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308-310, s. 290-293
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Tidskriftsartikel (refereegranskat)abstract
- The local vibrational modes of thermal double donors in Si and Ge are investigated by FTIR and ab initio modelling. At most, two oxygen modes are detected from each donor, which exhibit regular shifts with increasing donor number. By using mixtures of 16O and 18O, it is found that in Si the upper band does not yield any new modes suggesting that any oxygen atom is decoupled from any other. However, the lower frequency bands exhibit unique mixed modes proving for the first time that oxygen atoms are coupled together and in close spatial proximity. Ab initio calculations demonstrate that the modes and their isotopic shifts are consistent with a model involving two parallel chains of oxygen atoms linking second neighbour Si atoms, terminated by O-atoms close to the normal position for interstitial O. © 2001 Elsevier Science B.V. All rights reserved.
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| 22. |
- Murin, L. I., et al.
(författare)
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The oxygen dimer in Si: Its relationship to the light-induced degradation of Si solar cells?
- 2011
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 98:18
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Tidskriftsartikel (refereegranskat)abstract
- It is widely believed that the light induced degradation of crystalline silicon solar cells is due to the formation of a BsO2i recombination center created by the optically excited migration of the oxygen dimer (charge-state-driven motion). In this letter the concentration dependence of the neutral state of O-2i on [O-i] in p- and n-type Cz-Si has been determined using infrared absorption. A systematic search for the absorption signature of the dimer in the doubly positively charged state has been unsuccessful. These data strongly suggest that charge-state-driven motion (Bourgoin-Corbett mechanism) of the oxygen dimer cannot occur in typical solar silicon and hence bring into question the accepted degradation mechanism. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3584138]
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| 23. |
- Murin, L I, et al.
(författare)
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Thermal double donor annihilation and oxygen precipitation at around 650 degrees C in Czochralski-grown Si: local vibrational mode studies
- 2005
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 17:22, s. 2237-2246
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Tidskriftsartikel (refereegranskat)abstract
- We have used local vibrational mode (LVM) spectroscopy to monitor the formation of oxygen-related thermal double donors (TDDs) at 45 0 degrees C and their annihilation at 650 degrees C in carbon-lean Czochralski-grown (Cz-) Si crystals. A few samples were treated at 650 degrees C under high hydrostatic pressure. It is found that the annihilation of TDDs at 650 degrees C results not only in a partial recovery of the interstitial oxygen, but also in the appearance of a number of new O-related LVM bands in the range 990-1110 cm(-1). The positions of these lines and their shapes are identical to those observed for Cz-Si irradiated with electrons or neutrons and annealed at 600-700 degrees C. Since the lines appear upon annealing out of VO3 and VO4 defects in irradiated samples, they are suggested to arise from VOm (m > 4) complexes. In both kinds of samples, pre-annealed and preirradiated, the new LVM bands disappear upon prolonged annealing at 650 degrees C while enhanced oxygen precipitation occurs. The VOm defects are suggested to serve as nuclei for oxygen precipitates developing at around 650 degrees C. High hydrostatic pressure is found to enhance further (up to 4-5 times) the oxygen precipitation process at 650 degrees C in the samples pre-annealed at 450 degrees C.
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| 24. |
- Murin, L. I., et al.
(författare)
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Trivacancy-oxygen complex in silicon: Local vibrational mode characterization
- 2009
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Ingår i: Physica B: Condensed Matter. - : Elsevier BV. - 0921-4526. ; 404:23-24, s. 4568-4571
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Konferensbidrag (refereegranskat)abstract
- FTIR study of the evolution of multivacancy-oxygen-related defects in the temperature range 100-350 degrees C in Czochralski-grown Si samples irradiated with different particles (10 MeV electrons and 5 MeV neutrons) has been carried out. Appearance of two absorption bands positioned at 833.4 and 842.4 cm(-1) has been found upon annealing of the divacancy related absorption band at 2767 cm(-1). The 833.4 cm(-1) band is assigned to a divacancy-oxygen defect. The 842.4 cm band is much more pronounced in neutron irradiated samples and we argue that it is related to a trivacancy-oxygen defect formed via interaction of mobile V-3 with O-i atoms. (C) 2009 Elsevier B.V. All rights reserved.
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| 25. |
- Murin, L I, et al.
(författare)
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VOn (n >= 3) defects in irradiated and heat-treated silicon
- 2005
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Ingår i: Solid State Phenomena. - 1012-0394. ; 108-109, s. 267-272
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Tidskriftsartikel (refereegranskat)abstract
- Local vibrational mode (LVM) spectroscopy has been used to study the evolution of vacancy-oxygen-related defects (VOn) in the temperature range 300-700 degrees C in carbon-lean Cz-Si samples irradiated with MeV electrons or neutrons. New experimental data confirming an attribution of the absorption bands at 910, 976 and 1105 cm(-1) to the VO3 complex are obtained. In particular, a correlated generation of VO3 and the oxygen trimer is observed upon irradiation of CzSi crystals in the temperature range 300-400 degrees C. Strong evidence for the assignment of the bands at 991 and 1014 cm(-1) to a VO4 defect is presented. The lines are found to develop very efficiently in the VO2 containing materials enriched with the oxygen dimer. In such materials the formation of VO4 is enhanced due to occurrence of the reaction O-2i+VO2 double right arrow VO4. Annealing of the VO3 and VO4 defects at T >= 550C degrees C is found to result in the appearance of new defects giving rise to a number of O-related LVM bands in the range 990-1110 cm(-1). These bands are suggested to axise from VO5 and/or VO6 defects. Similar bands also appear upon the annihilation of oxygen-related thermal double donors at 650 degrees C in Cz-Si crystals pre-annealed at 450 degrees C.
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| 26. |
- Vaqueiro-Contreras, Michelle, et al.
(författare)
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Powerful recombination centers resulting from reactions of hydrogen with carbon–oxygen defects in n-type Czochralski-grown silicon
- 2017
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Ingår i: Physica Status Solidi. Rapid Research Letters. - : John Wiley & Sons. - 1862-6254 .- 1862-6270. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- It has been acknowledged for over 50 years that treatments with hydrogen can improve silicon semiconductor devices. In recent years, these have been used to an advantage in silicon solar cells reducing the loss of photo-generated carriers at the silicon surface or at the silicon interface with dielectrics. However, we have found that in some types of silicon the in-diffusion of hydrogen can result in the formation of powerful recombination centers composed of carbon, oxygen, and hydrogen which reduce the carrier lifetime and ultimately the efficiency of solar cells made from such material
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| 27. |
- Öberg, Sven, et al.
(författare)
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First stage of oxygen aggregation in silicon : the oxygen dimer
- 1998
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 81:14, s. 2930-2933
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Tidskriftsartikel (refereegranskat)abstract
- The structure and dynamic properties of the interstitial oxygen dimer in silicon are found using a combination of infrared spectroscopy and ab initio modeling. We find that the stable dimer consists of a pair of inequivalent weakly coupled interstitial oxygen atoms separated by a Si-Si bond. Two high frequency modes are decoupled in one 16O-18O combination but are strongly mixed in the other combination. A third lower lying mode involves the compression of the Si-Si bond joining the oxygen atoms and gives distinct modes in the mixed 16O-18O case.
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