Papers by Keyword: Intrinsic Defect

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Authors: Gerhard Pensl, Frank Schmid, Sergey A. Reshanov, Heiko B. Weber, M. Bockstedte, Alexander Mattausch, Oleg Pankratov, Takeshi Ohshima, Hisayoshi Itoh
Abstract: Nitrogen (N) donors in SiC are partially deactivated either by Si+-/N+-co-implantation or by irradiation with electrons of 200 keV energy and subsequent annealing at temperatures above 1450°C; simultaneously the compensation is decreased. The free electron concentration and the formation of energetically deep defects in the processed samples are determined by Hall effect and deep level transient spectroscopy. A detailed theoretical treatment based on the density functional theory is conducted; it takes into account the kinetic mechanisms for the formation of N interstitial clusters and (N-vacancy)-complexes. This analysis clearly indicates that the (NC)4-VSi complex, which is thermally stable up to high temperatures and which has no level in the band gap of 4HSiC, is responsible for the N donor deactivation.
Authors: Lars S. Løvlie, Lasse Vines, Bengt Gunnar Svensson
Abstract: 4H-SiC has been irradiated with 10 keV protons and a laterally resolved DLTS study performed to study the diffusion of irradiation induced intrinsic point defects. It is found that the defects migrate on the order of hundreds of μm laterally and carbon interstitials (CI) are believed to be involved in the defect formation. However, the vertical diffusion lengths are revealed to be several orders of magnitude shorter, on the order of hundreds of nm. Specifically, the Z1,2, S1,2 and EH6,7 levels are found to be generated significant distances from the irradiated area, suggesting that CI or another highly mobile species are involved in the formation of these defects.
Authors: E. Rauls, Uwe Gerstmann, M.V.B. Pinheiro, Siegmund Greulich-Weber, Johann Martin Spaeth
Abstract: In a combined theoretical and experimental work, we have investigated the common DI photoluminescence in 6H-SiC material. We present an atomistic model which is able to explain the annealing behavior, i. e. the correlation with the silicon vacancy, the local vibrational modes and the excitonic-like character observed.
Authors: Z. Zolnai, Nguyen Tien Son, Björn Magnusson, Christer Hallin, Erik Janzén
Authors: B. Aradi, Adam Gali, Peter Deák, E. Rauls, Thomas Frauenheim, Nguyen Tien Son
Authors: M.V. Zamoryanskaya
Abstract: In this paper the new method for determination of luminescent centers concentration are discussed. While the possibility of electron traps determination and definition of its activation energy are suggested. The cathodoluminescent (CL) method was used. The determination of luminescent centers concentration in silicon oxide is based on the measurements of dependences of CL intensity on electron beam current. The presence and energy of activation of electron traps were studied by measurement of rise time and decay of luminescent band during the stationary irradiation of silica by electron beam.
Authors: Katsunori Danno, Tsunenobu Kimoto
Abstract: Deep levels in as-grown p-type 4H-SiC epilayers have been investigated by DLTS. Three deep hole traps (HK2, HK3 and HK4) can be detected by DLTS in the temperature range from 350K to 700K. They are energetically located at 0.84 eV (HK2), 1.27 eV (HK3) and 1.44 eV (HK4) above the valence band edge. The activation energy of the traps does not show any meaningful change regardless of applied electric field, indicating that the charge state of the deep hole traps may be neutral after hole emission (donor-like). By the low-energy electron irradiation, the HK3 and HK4 concentrations are significantly increased, suggesting that the origins of the HK3 and HK4 may be related to carbon displacement. Study on the thermal stability of these hole traps has revealed that the trap concentrations of HK3 and HK4 are reduced to below the detection limit (1-2 × 1011 cm-3) by annealing at 1350°C. The HK2 is thermally more stable than HK3 and HK4, and becomes lower than the detection limit by annealing at 1550°C.
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