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EBIC studies on fluorinated grain boundaries and dislocations
Published in A G Cullis, P D Augustus, Microscopy of Semiconducting Materials, 1987, 2021
F G Kuper, J Th M de Hosson, J F Verwey
To study the electrical properties of defects after passivation one can measure overall quantities, like the resistivity along and perpendicular to grain boundaries like Ginley (1981) and Maby and Antoniadis (1982), or the generation time constant of a wafer, with a Zerbst experiment (Zerbst 1966). In contrast, the electrical recombination activity of defects can be measured locally using Electron Beam Induced Current (EBIC) which has a resolution between 1 and 10 micrometers depending on beam energy and material quality according to Marek (1982) and Leamy (1982). EBIC combines defect observation with an electrical measurement, because the intensity displayed on the screen corresponds to the local recombination of excess electron/hole pairs. An example is shown in figure 1, in which an optical picture of an etched sample and an EBIC picture of a comparable but unetched sample can be compared. It is seen that the major electrical activity of a stacking fault is confined to the bounding Frank partial dislocation. Here dangling bonds can be expected.
Characterization of Electrodeposits and Electrodeposition Processes
Published in R.K. Pandey, S.N. Sahu, S.N. Sahu, S. Chandra, Handrook Of Semiconductor Electrodeposition, 2017
R.K. Pandey, S.N. Sahu, S.N. Sahu, S. Chandra
Electron Beam Induced Current Technique (EBIC). Information can also be obtained about diffusion length if current modulation is attained by an electron beam probing the surface (instead of photons, which give changes in photoconductivity). This technique is referred to as EBIC and generally comes as an attachment of a SEM that operates in the charge collection mode. In this mode, a voltage is applied across the specimen, which is simultaneously flushed with an electron beam at a distance x from the point where the excess carriers are collected. A large number of these excess carriers are generated because of the absorption of energy of the incident beam yielding an electron beam induced current (EBIC) signal given as iEBIC=Aexp(-xL)
SEM investigations of individual extended defects in GaN epilayers
Published in A. G. Cullis, P. A. Midgley, Microscopy of Semiconducting Materials 2003, 2018
N M Shmidt, V V Sirotkinl, A S Usikov, E B Yakimov, E E Zavarin
The increasing application of III-nitrides in light emitting diodes, lasers and advanced electronic devices generates interest in the study of electrical and optical properties of defects in these materials. The dislocation properties in GaN are particularly intriguing because high-performance light emitting diodes and lasers have been fabricated using GaN despite a density of dislocations (typically in the range from 108 to 10 10 cm.2) that is high enough to degrade the device performance in other III-V materials. In spite of widespread efforts, there have been many conflicting views on the role of the threading dislocations in GaN (Jain et a! 2000, Yakimov 2002). Therefore, it is very important from both scientific and practical points of view to study recombination properties of individual dislocations in GaN, their dependence on temperature, excitation level and impurity content. One of the methods widely used for the study of individual extended defects, which could provide quantitative information about their recombination properties, is the electron beam induced current (EBIC) mode of the scanning electron microscope (Alexander 1994, Kittler and Seifert 1996). The model of extended defect EBIC contrast was developed (Donolato 1992), which allowed not only the description of the contrast profile but also the extraction of the dislocation recombination strength value from the EBIC contrast. The recombination strength plays a role similar to that of surface recombination velocity for two-dimensional defects and can be considered as an important parameter describing quantitatively the dislocation effect on the excess carrier distribution and recombination rate. However, in traditional semiconductor crystals, such as Si and GaAs, the EBIC can be effectively used for the characterisation of individual dislocations only in the case when their density does not exceed 106-107 cm·2 · As mentioned above, the dislocation density in GaN structures usually essentially exceeds this value. Nevertheless, in this material individual defect properties can be studied even if their density exceeds 109cm·2 because the low value of minority carrier diffusion length allows essentially the improvement of the lateral resolution in the EBIC method (Shmidt et a! 2002). In the present paper GaN layers grown by MOCVD on sapphire substrates have been studied. The results of the EBIC investigations of individual dislocations perpendicular to the surface are presented. It is observed that the dislocation EBIC profile width decreases with increasing primary electron energy, which is explained by the small diffusion length in the structures under study. The profiles of dislocation EBIC contrast have been studied and compared with simulated ones. The dislocation recombination strength and the diffusion length in dislocation-free regions have been
Impact of neutron irradiation on electronic carrier transport properties in Ga2O3 and comparison with proton irradiation effects
Published in Radiation Effects and Defects in Solids, 2023
Jonathan Lee, Andrew C. Silverman, Elena Flitsiyan, Minghan Xian, Fan Ren, S. J. Pearton
The samples before and after exposure to the neutron and proton doses were characterized for changes in various parameters by current–voltage (I-V), capacitance–voltage (C-V), reverse recovery, on/off ratio, Schottky barrier height, diode ideality factor, Cathodoluminescence (CL) intensity, and EBIC (Electron Beam Induced Current). CL measurements were collected in-situ with Philips XL-30 SEM. The basic CL setup is presented in Figure 8. The XL-30 SEM is equipped with a Gatan MonoCL3, which collects light with a parabolic mirror and monochromator. The monochromate signal outputs to a photomultiplier tube (PMT), sensitive from 180 to 850 nm. The temperature range used for experiments in the XL-30 is restricted to vary between 80 and 393 K. The available acceleration voltages range from 3 to 30 kV.