| 1. |
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| 2. |
- Gali, Ádám, et al.
(författare)
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Point defects in SiC
- 2008
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Konferensbidrag (refereegranskat)abstract
- Tight control of defects is pivotal for semiconductor technology. However, even the basic defects are not entirely understood in silicon carbide. In the recent years significant advances have been reached in the identification of defects by combining the experimental tools like electron paramagnetic resonance and photoluminescence with ab initio calculations. We summarize these results and their consequences in silicon carbide based technology. We show recent methodological developments making possible the accurate calculation of absorption and emission signals of defects.
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| 3. |
- Gali, Adam, et al.
(författare)
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Theory of Spin-Conserving Excitation of the N-V- Center in Diamond
- 2009
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Ingår i: PHYSICAL REVIEW LETTERS. - 0031-9007. ; 103:18, s. 186404-
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Tidskriftsartikel (refereegranskat)abstract
- The negatively charged nitrogen-vacancy defect in diamond is an important atomic-scale structure that can be used as a qubit in quantum computing and as a marker in biomedical applications. Its usefulness relies on the ability to optically excite electrons between well-defined gap states, which requires a clear and detailed understanding of the relevant states and excitation processes. Here we show that by using hybrid density-functional-theory calculations in a large supercell we can reproduce the zero-phonon line and the Stokes and anti-Stokes shifts, yielding a complete picture of the spin-conserving excitation of this defect.
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| 4. |
- Isoya, J, et al.
(författare)
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Pulsed EPR studies of phosphorus shallow donors in diamond and SiC
- 2006
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Ingår i: Physica B, Vols. 376-377. - : Elsevier BV. ; , s. 358-361
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Konferensbidrag (refereegranskat)abstract
- Phosphorus shallow donors having the symmetry lower than T-d are studied by pulsed EPR. In diamond:P and 3C-SiC:P, the symmetry is lowered to D-2d and the density of the donor wave function on the phosphorus atom exhibits a predominant p-character. In 4H-SiC:P with the site symmetry of C-3v, the A(1) ground state of the phosphorus donors substituting at the quasi-cubic site of silicon shows an axial character of the distribution of the donor wave function in the vicinity of the phosphorus atom. (c) 2005 Elsevier B.V. All rights reserved.
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| 5. |
- Janzén, Erik, 1954-, et al.
(författare)
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Defects in SiC
- 2008
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Ingår i: Defects in Microelectronic Materials and Devices. - : Taylor and Francis LLC. ; , s. 770-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Uncover the Defects that Compromise Performance and Reliability As microelectronics features and devices become smaller and more complex, it is critical that engineers and technologists completely understand how components can be damaged during the increasingly complicated fabrication processes required to produce them.A comprehensive survey of defects that occur in silicon-based metal-oxide semiconductor field-effect transistor (MOSFET) technologies, this book also discusses flaws in linear bipolar technologies, silicon carbide-based devices, and gallium arsenide materials and devices. These defects can profoundly affect the yield, performance, long-term reliability, and radiation response of microelectronic devices and integrated circuits (ICs). Organizing the material to build understanding of the problems and provide a quick reference for scientists, engineers and technologists, this text reviews yield- and performance-limiting defects and impurities in the device silicon layer, in the gate insulator, and/or at the critical Si/SiO2 interface. It then examines defects that impact production yield and long-term reliability, including:Vacancies, interstitials, and impurities (especially hydrogen)Negative bias temperature instabilitiesDefects in ultrathin oxides (SiO2 and silicon oxynitride)Take A Proactive Approach The authors condense decades of experience and perspectives of noted experimentalists and theorists to characterize defect properties and their impact on microelectronic devices. They identify the defects, offering solutions to avoid them and methods to detect them. These include the use of 3-D imaging, as well as electrical, analytical, computational, spectroscopic, and state-of-the-art microscopic methods. This book is a valuable look at challenges to come from emerging materials, such as high-K gate dielectrics and high-mobility substrates being developed to replace Si02 as the preferred gate dielectric material, and high-mobility substrates
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| 6. |
- Janzén, Erik, 1954-, et al.
(författare)
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The Silicon vacancy in SiC
- 2009
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Konferensbidrag (refereegranskat)abstract
- A model is presented for the silicon vacancy in SiC. The previously reported photoluminescence spectra in 4H and 6H SiC attributed to the silicon vacancy are in this model due to internal transitions in the negative charge state of the silicon vacancy. The magnetic resonance signals observed are due to the initial and final states of these transitions.
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| 7. |
- Janzén, Erik, et al.
(författare)
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The silicon vacancy in SiC
- 2009
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Ingår i: Physica. B, Condensed matter. - : Elsevier. - 0921-4526 .- 1873-2135. ; 404:22, s. 4354-4358
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Tidskriftsartikel (refereegranskat)abstract
- The isolated silicon vacancy is one of the basic intrinsic defects in SiC. We present new experimental data as well as new calculations on the silicon vacancy defect levels and a new model that explains the optical transitions and the magnetic resonance signals observed as occurring in the singly negative charge state of the silicon vacancy in 4H and 6H SiC.
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| 8. |
- Nguyen, Son Tien, 1953-, et al.
(författare)
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Defects introduced by electron-irradiation at low temperatures in SiC
- 2009
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Ingår i: Materials Science Forum Vols. 615-617. - : Trans Tech Publicarions. - 9780878493340 ; , s. 377-380
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Konferensbidrag (refereegranskat)abstract
- Defects introduced by electron irradiation at ~80-100 K in 3C-, 4H- and 6H-SiC were studied by electron paramagnetic resonance (EPR). A number of EPR spectra, labelled LE1-10, were detected. Combining EPR and supercell calculations, we will show that the LE1 center in 3C-SiC with C2v symmetry and an electron spin S=3/2 is related to the (VSi-Sii)3+ Frenkel pair between the silicon vacancy and a second neighbour Sii interstitial along the <100> direction. Results on other centers, possibly also related to interstitials, are discussed.
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| 9. |
- Nguyen, Son Tien, et al.
(författare)
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Identification of a Frenkel-pair defect in electron-irradiated 3C SiC
- 2009
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 80, s. 125201-
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Tidskriftsartikel (refereegranskat)abstract
- Anelectron paramagnetic resonance (EPR) spectrum labeled LE1 was observed inn-type 3C SiC after electron irradiation at low temperatures (~80–100 K).A hyperfine interaction with four nearest C neighbors similar tothat of the well-known silicon vacancy in the negative chargestate was observed, but the LE1 center has a lowersymmetry, C2v. Supercell calculations of different configurations of silicon vacancy-interstitialFrenkel-pairs, VSi-Sii, were performed showing that pairs with a nearestneighbor Si interstitial are unstable—VSi and Sii will automatically recombine—whereaspairs with a second neighbor Sii are stable. Comparing thedata obtained from EPR and supercell calculations, the LE1 centeris assigned to the Frenkel-pair between VSi and a secondneighbor Sii interstitial along the [100] direction in the 3+charge state, V-Si. In addition, a path for the migrationof Si was found in 3C SiC. In samples irradiatedat low temperatures, the LE1 Frenkel-pair was found to bethe dominating defect whereas EPR signals of single vacancies werenot detected. The center disappears after warming up the samplesto room temperature.
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| 10. |
- Nguyen, Tien Son, et al.
(författare)
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Identification of divacancies in 4H-SiC
- 2006
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Ingår i: Physica B: Condensed Matter, Vols. 376-377. - : Elsevier BV. ; , s. 334-337
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Konferensbidrag (refereegranskat)abstract
- The P6/P7 centers in 4H-SiC were studied by electron paramagnetic resonance (EPR) and ab initio supercell calculations. The hyperfine coupling constants of C and Si neighbors obtained by EPR are in good agreement with the calculated values for the neutral divacancy, VCVsi0. Our results suggest that the P6/P7 centers, which were previously assigned to the photo-excited triplet states of the carbon vacancy-carbon antisite pairs in the double positive charge state (VCCsi2+), are related to the triplet ground states of the C-3v/C-1h si configurations of VCVsi0 (c) 2006 Elsevier B.V. All rights reserved.
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