Electron Beam Induced Current Mode Research Articles

EBIC investigations of dislocations in ELOG GaN

AbstractDislocations in the ELOG n‐GaN films have been studied by the Electron Beam Induced Current (EBIC) method. The effect of dopant concentration and diffusion length values on the dislocation EBIC profile is revealed. It is shown that the width of dislocation image in the EBIC mode decreases with a diffusion length decrease and the dopant concentration increase. In the crystals with the submicron diffusion length the individual dislocations can be separated in the EBIC images up to the dislocation densities higher that 109cm‐2. The radius of dislocation related defect cylinder was found to increase with the dopant concentration decreasing that could be explained under an assumption that dislocations in GaN are charged. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Investigation of stacking faults in 4H-SiC using the electron-beam-induced current method

Stacking faults in 4H-SiC crystals introduced upon plastic deformation at 550°C are studied using the electron-beam-induced current (EBIC) method. The types of stacking faults are determined by measuring the cathodoluminescence spectra. The stacking faults are shown to give a bright contrast in the EBIC mode. The nature of such contrast is discussed. The possibility of increasing the efficiency of semiconductor detectors based on structures with stacking faults equivalent to thin 3C-SiC layers is demonstrated.

Influence of metal impurities on recombination activity of dislocations in multicrystalline silicon

The influence of Fe, Cu, and Ni atoms introduced by means of high-temperature diffusion on the recombination properties of dislocations in multicrystalline silicon is investigated by the electron-beam induced-current (EBIC) method. It is shown that the influence of all three impurities is qualitatively similar. Recombination activity of dislocations remains lower than the detection limit in the EBIC mode both for starting samples and after the diffusion of transition metals. The behavior of dislocations is interpreted under the assumption that dislocations are already impurity-saturated in starting samples.

Comparison between the EBIC and XBIC contrasts of dislocations and grain boundaries

The X-ray-beam-induced current (XBIC) method is used to calculate the contrasts of dislocations and grain boundaries perpendicular to a surface as a function of the diffusion length of minority charge carriers and the X-ray probe width. The results are compared with the contrasts of the same defects determined via the electron-beam-induced current (EBIC) techniques. It is demonstrated that the XBIC contrasts of grain boundaries and dislocations can be several times greater than those obtained in the EBIC mode in the case of a rather narrow X-ray beam. The XBIC contrast always exceeds that of EBIC in semiconductors with a large diffusion length even if the X-ray beam is rather wide.

EBIC investigations of defect distribution in ELOG GaN films

Abstract The possibilities of the Electron Beam Induced Current (EBIC) method for the characterization of epitaxial lateral overgrowth (ELOG) GaN structures are demonstrated. The diffusion length and local donor concentrations in the structures studied are obtained by fitting the dependence of collected current in the EBIC mode on accelerating voltage with calculated one. It is shown that the local donor concentrations in the regions of lateral overgrowth measured by the EBIC are about three times lower than that in the vertically grown regions. This difference is observed in the structures with the donor concentration varying in the range from 10 15 to 10 17 cm −3 . These results could be ascribed to the anisotropy of Si incorporation efficiency during growth. A comparison of the EBIC results with the results of capacitance–voltage ( C – V ) profiling allows us to estimate the precision of EBIC dopant concentration measurements.

A novel method of determining semiconductor parameters in EBIC and SEBIV modes of SEM

We present a novel method for determining semiconductor parameters such as diffusion length L, lifetime τ and surface recombination velocity S of minority carriers by employing scanning electron microscopy (SEM). This new method is applicable to both electron beam induced current (EBIC) and surface electron beam induced voltage (SEBIV) modes in SEM. The quantitative descriptions for EBIC and SEBIV signals are derived. The parameters L, S and τ can be directly extracted from the expressions for EBIC or SEBIV signals and their relaxation characteristics in experiment. As an example, the values of L, S and τ for n–p junction and p-Si crystal are determined by using the novel method in EBIC or SEBIV mode. The carrier diffusion length of a p-Si crystal is determined to be 8.74 μm in SEBIV mode. It is very close to the normal diffusion length of 7.41 μm of this sample. The novel method is proved to be very helpful for the quantitative characterization of semiconductor materials and devices. Especially, the SEBIV mode in SEM shows great potential for investigating semiconductor structures nondestructively.

Microcharacterization of Polycrystalline Semiconductors by Scanning Electron Microscopy in Electron Beam Induced Current Mode

Microcharacterization of Polycrystalline Semiconductors by Scanning Electron Microscopy in Electron Beam Induced Current Mode

LBIC QUANTITATIVE MAPPING

The method of electron beam induced current (EBIC) characterization has been widely used. However, many of experiments possible with the EBIC mode can be performed using a light-beam as an excitation source. The aim of this paper is to give a review of the physical parameters that may be obtained using the light-beam induced current (LBIC) method. Theoretical models involved for quantitative interpretation of LBIC signal and some typical applications are reviewed. The conditions to obtain quantitative mapping are discussed. Some examples including Schottky barriers, solar cells and bipolar transistor are given.

Scanning electron microscope charge-collection images of grain boundaries

Images of grain boundaries obtained in the scanning electron microscope operated in the electron beam-induced current mode are calculated. Images of boundaries in semicrystalline silicon solar cells are measured in the experiment and agree within 2% with theory. The calculated profiles depend strongly on the diffusion length of the semiconductor, providing a new method for determining the diffusion length of the material.

A study of diffused bipolar transistors by electron microscopy

Shallow junction bipolar transistors have been fabricated on bulk (001) silicon starting material using a diffusion processing technology. The resultant junction depths were about 0.5 and 0.8 μ m respectively for the emitter-base and base-collector junctions. The crystallographic defects present have been detected and characterized using a combination of electrical measurements, the electron beam induced current (EBIC) mode of the scanning electron microscope (SEM) and both conventional and high voltage transmission electron microscopy (TEM). Two types of dislocations were identified in the TEM. The first consisted of an orthogonal array of sessile, diffusion-induced edge dislocations located about halfway down in the heavily doped emitter. The second type consisted of 60° glissile dislocations that looped down from the orthogonal array and in some cases penetrated the emitter-base junction. Observations of a number of 60° dislocations yielded a good correlation between their depth and their contrast when imaged in the EBIC mode of the SEM. The 60° dislocations locally retard the emitter diffusion when they lie near to the emitter-base junction. Local breakdown effects under reverse bias were observed at the sites of these dislocations.

Applications of the scanning electron microscope EBIC mode to semiconductor device evaluation and failure analysis

This paper shows how the Electron Beam Induced Current (EBIC) mode of operation finds routine application in the failure analysis and evaluation of semiconductor devices for space application. Most of the previously published work on EBIC has been of a theoretical nature and has concentrated on the quantitative aspect such as the measurement of minority carrier lifetime. The EBIC mode, however, also lends itself to the qualitative evaluation and analysis of comparatively complex semiconductor devices and in particular the study of diffusion spikes and similar effects. The routine application of the EBIC mode to practical device analysis is described and illustrated by case histories of device problems. Improvements in experimental techniques are proposed based on the work presented.

Component quality assurance: which plan is better? : Martin Vyenielo. Electronics p. 97. (September 30 1976)

Shallow junction bipolar transistors have been fabricated on bulk (001) silicon starting material using a diffusion processing technology. The resultant junction depths were about 0.5 and 0.8 μ m respectively for the emitter-base and base-collector junctions. The crystallographic defects present have been detected and characterized using a combination of electrical measurements, the electron beam induced current (EBIC) mode of the scanning electron microscope (SEM) and both conventional and high voltage transmission electron microscopy (TEM).Two types of dislocations were identified in the TEM. The first consisted of an orthogonal array of sessile, diffusion-induced edge dislocations located about halfway down in the heavily doped emitter. The second type consisted of 60° glissile dislocations that looped down from the orthogonal array and in some cases penetrated the emitter-base junction.Observations of a number of 60° dislocations yielded a good correlation between their depth and their contrast when imaged in the EBIC mode of the SEM. The 60° dislocations locally retard the emitter diffusion when they lie near to the emitter-base junction. Local breakdown effects under reverse bias were observed at the sites of these dislocations.