Papers by Keyword: EBIC

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Authors: Y. Yanagisawa, Tomoaki Hatayama, Hiroshi Yano, Yukiharu Uraoka, Takashi Fuyuki
Abstract: Propagations of dislocations in 4H-SiC were evaluated three-dimensionally by a planar mapping EBIC method with the control of accelerating voltages. Screw dislocation (SD), edge dislocation (ED), and basal plane dislocation (BPD) were clearly observed through the 20nm-thick Ni Schottky contact on SiC. From the analysis of BPD extended on {0001}, the intensity of EBIC signals was proportional to the depth position of defect. In addition, the information of the decomposition and combination for dislocations can be obtained from the fluctuation of EBIC signal along the scanning position.
Authors: Valeri I. Orlov, Olga V. Feklisova, Eugene B. Yakimov
Abstract: A comparative study of multicrystalline Si based solar cells and plastically deformed single crystalline Si by the EBIC, LBIC and XBIC methods as well as a computer simulation were carried out. The XBIC measurements were realized on a laboratory X-ray source. Simulations of LBIC and XBIC contrast values for grain boundaries, dislocations and spherical precipitates were carried out for different diffusion length and beam diameter values. It is shown by a computer simulation that the LBIC and XBIC contrast of two-dimensional defects in the crystals with a large enough diffusion length can be a few times higher than that in the EBIC mode, i.e. these methods in recent multicrystalline Si structures allow to reveal grain boundaries with the lower recombination strength. The contrast of dislocations perpendicular to the surface can be comparable in all three methods. The XBIC and LBIC contrast of precipitates usually is essentially smaller than that in the EBIC mode and could approach it in the structures with the small diffusion length only. Experimental data confirming the results of simulations are presented.
Authors: Winfried Seifert, Daniel Amkreutz, Tzanimir Arguirov, Hans Michael Krause, Manfred Schmidt
Abstract: The properties of electron-beam crystallized, large-grained silicon layers of about 10 µm thickness on glass have been studied by combining EBIC, EBSD and photoluminescence. It is found that most grains are free of dislocations. From a detailed analysis based on the dependence of EBIC collection efficiency on beam energy we conclude that the recombination properties of the layers are mainly determined by the bulk diffusion length. The estimated bulk diffusion length in the dislocation-free layer regions is in the range of roughly 5 – 7 µm, depending on the recombination velocity assumed for the rear surface. In dislocated regions the diffusion length drops to 1 µm or less. Close to some twin boundaries, an unsusual improvement of the electrical layer properties has been observed. In addition, wave-like inhomogeneities of the layer properties have been established, resulting probably from instabilities during the crystallization process.
Authors: M. Holla, Tzanimir Arguirov, Winfried Seifert, Martin Kittler
Abstract: We report on the optical and mechanical properties of Si3N4 inclusions, formed in the upper part of mc-Si blocks during the crystallization process. Those inclusions usually appear as crystalline hexagonal tubes or rods. Here we show that in many cases the Si3N4 inclusions contain crystalline Si in their core. The presence of the Si phase in the centre was proven by means of cathodoluminescence spectroscopy and imaging, electron beam induced current measurements and Raman spectroscopy. The crystalline Si3N4 phase was identified as β-Si3N4. Residual stress was revealed at the particles. While the stress is compressive in the Si material surrounding the Si3N4 particles tensile stress is found in the Si core. We assume that the stress is formed during cool down of the Si block and is a consequence of the larger thermal expansion coefficient of Si in comparison to that of β-Si3N4. Iron assisted nitridation of Si at temperatures below 1400 °C is considered a possible mechanism of Si3N4 formation.
Authors: Stanislav I. Soloviev, Peter A. Losee, Stephen Arthur, Zachary Stum, Jerome L. Garrett, Ahmed Elasser
Abstract: Bipolar degradation in 4H-SiC thyristors subjected to high current density stress is reported. The thyristor device structure, its fabrication process as well as testing conditions are described. The Electron Beam Induced Current (EBIC) technique was used for defect analysis in testing of both degraded and non-degraded devices. Possible nucleation sites responsible for the generation of observed defects in degraded devices are discussed
Authors: J. Chen, Takashi Sekiguchi, S. Ito, De Ren Yang
Abstract: The carrier recombination activities of small angle (SA) grain boundaries (GBs) in multicrystalline Si (mc-Si) were systematically investigated by electron-beam-induced current (EBIC). At 300 K, general SA-GBs with tilt angle from 0° to 10° showed weak EBIC contrast (0- 10%) with the maximum appeared at 2°. At low temperature (100 K), all the SA-GBs showed strong EBIC contrast despite the tilt angle. Possible explanations for the variation of the EBIC contrast were discussed in terms of boundary dislocations.
Authors: Philipp Saring, Anna Lena Baumann, Stefan Kontermann, Wolfgang Schade, Michael Seibt
Abstract: This paper investigates the influence of different number of laser pulses on contact behavior and conductivity of the surface layer of femtosecond laser microstructured, sulfur-doped silicon. Single shot laser processed silicon (Pink Silicon) is characterized by low surface roughness, whereas five shot laser processed silicon (Grey Silicon) has an elevated sulfur content with a surface roughness low enough to maintain good contacting. To laterally confine the laser induced pn-junction part of the Grey Silicon sample surface is etched off. The etching depth is confirmed to be sufficient to completely remove the active n-type sulfur layer. While Pink Silicon shows little or no lateral conductivity within the laser processed layer, Grey Silicon offers acceptable conductivity, just as expected by the fact of having incorporated a higher sulfur dopant content. Recombination dominates the irradiated regions of Pink Silicon and suppresses excess charge carrier collection. Grey Silicon, while showing sufficient lateral conductivity, still shows regions of lower conductivity, most likely dominated by the laser irradiation-induced formation of dislocations. According to our results, the optimum laser pulse number for electrical and structural properties is expected to be in the range between one and five laser pulses.
Authors: Y. Wang, L. Chen, M.K. Mikhov, G. Samson, B.J. Skromme
Abstract: Formation of I1 Shockley stacking faults by recombination-enhanced defect glide in 4HSiC p-i-n diodes subject to high forward current stress is studied in diodes on both c-oriented and aoriented substrates. The forward voltage increases during stressing for both orientations, accompanied by nucleation and expansion of faults visible in electroluminescence (EL) imaging. Low temperature photoluminescence (PL) measurements on degraded diodes of both orientations reveal the same set of exciton peaks, confirming that the electronic structure of the faults is the same in both cases. The spectroscopic data are compared to self-consistent solutions of the Schrödinger and Poisson equations including polarization charge. Dislocations nucleating the faults are bright in EL images but dark in electron beam-induced current (EBIC) imaging, confirming that they are sites of enhanced radiative recombination.
Authors: O.V. Kononchuk, I.E. Bondarenko, George A. Rozgonyi
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