| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- Song, Aimin, et al.
(författare)
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Unidirectional electron flow in a nanometer-scale semiconductor channel: A self-switching device
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 83:9, s. 1881-1883
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Tidskriftsartikel (refereegranskat)abstract
- By tailoring the boundary of a narrow semiconductor channel to break its symmetry, we have realized a type of nanometer-scale nonlinear device, which we refer to as self-switching device (SSD). An applied voltage V not only changes the potential profile along the channel direction, but also either widens or narrows the effective channel depending on the sign of V. This results in a diode-like characteristic but without the use of any doping junction or barrier structure. The turn-on voltage can also be widely tuned from virtually zero to more than 10 V, by simply adjusting the channel width. The planar and two-terminal structure of the SSD also allows SSD-based circuits to be realized by only one step of lithography. (C) 2003 American Institute of Physics.
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