Papers by Keyword: EBIC

Abstract: Lateral gate depletion expansion towards drain contact has been analyzed on p-type diamond metal-semiconductor field effect transistor by electron beam induced current. The investigation was restricted to a closed channel to simplify the study and to directly observe the expansion of the lateral depletion region. The experimental data agreed with the theoretical model given in the literature.

Abstract: Commercial 4H-SiC p⁺n structures with an uncompensated donor concentration (N_d-N_a) of ~1.5∙10¹⁵ cm^-3 in the n-type epitaxial layer are studied. The measurement of the photocurrent, electron beam induced current and transient switching characteristics (from forward to reverse voltage), altogether showed that the value of the hole diffusion length, about 2 μm at room temperature, increases to at least 7 μm at 620 K.

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.

Abstract: We report on 0.93 eV luminescence observed in multicrystalline silicon. The spectral line is close to the well known D3 one, but its properties are different. The new feature shows a remarkable intensity at room temperature, exceeding the intensity of the band to band radiative transition. Moreover, it appears as a single line in the entire temperature range 10-300K, in contrast to the D3, which is usually accompanied by D4. Cathodoluminescence (CL) and electron beam induced current (EBIC) micrographs revealed that the centers causing 0.93 eV emission are irregularly distributed along certain grain boundaries. Electron backscattering diffraction examination showed that the 0.93 eV luminescence appears at grain boundaries characterized by a lattice rotation around a <344> axis. The EBIC contrast at those irregularities indicates strong total recombination. Based on an analysis of the temperature dependence of the CL intensity and the EBIC contrast we obtained an activation energy of about 120 meV.

Abstract: Protons with energies of 1 MeV and 2.5 MeV were implanted into a p-doped silicon wafer and then the wafer was annealed at 350 °C for one hour. This resulted in two n-doped layers in the otherwise p-doped sample. The carrier concentration was measured using spreading resistance profiling while the positions of the four pn-junctions were measured using electron beam induced current measurements. The carrier concentration is not limited by the available hydrogen but by the concentration of suitable radiation induced defects.

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.

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

Abstract: Quantitative efficacies of several methods for stacking fault (SF) reduction are evaluated using Monte Carlo (MC) simulation. SF density on a 3C–SiC {001} surface depends on interactions of adjoining SFs: annihilation between counter pairs of SFs and termination by orthogonal SF pairs. However, SFs are not entirely eliminated when growth occurs on undulant-Si and switch back epitaxy (SBE) due to spontaneous SF collimation that suppresses the annihilation probability of counter SFs. The MC simulation also reveals the efficacy of SF reduction method which includes the growth of 3C–SiC on finite area bounded by side walls. One can theoretically reduce the SF density below 100 cm^-1 on 3C–SiC {001} surface. A practical way for eliminating the SF by termination at side walls is demonstrated, and it clearly exhibits that the SF density can be reduced under 120 cm^-1.

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.

Abstract: Investigations of silicon layers grown on carbon foil were carried out using the Electron Beam Induced Current (EBIC) methods. The most of grain boundaries in these ribbons are (111) twin boundaries elongated along the direction. The EBIC measurements showed that the recombination contrast of dislocations and of the most part of twin boundaries at room temperature is practically absent and only random grain boundaries and very small part of twin boundaries produce a noticeable contrast. At lower temperatures a number of electrically active twin boundaries increases but the most part of them remains inactive. A contamination with iron increases the recombination activity of random boundaries but not the activity of twin boundaries.