EBIC Imaging Research Articles

Nano-PUND and STEM EBIC Imaging for Ferroelectric Polarization Mapping

Nano-PUND and STEM EBIC Imaging for Ferroelectric Polarization Mapping

Mapping Moiré Potentials with STEM EBIC Imaging

Mapping Moiré Potentials with STEM EBIC Imaging

Identification of localized radiation damage in power MOSFETs using EBIC imaging

The rapidly increasing use of electronics in high-radiation environments and the continued evolution in transistor architectures and materials demand improved methods to characterize the potential damaging effects of radiation on device performance. Here, electron-beam-induced current is used to map hot-carrier transport in model metal-oxide semiconductor field-effect transistors irradiated with a 300 KeV focused He+ beam as a localized line spanning across the gate and bulk Si. By correlating the damage to the electronic properties and combining these results with simulations, the contribution of spatially localized radiation damage on the device characteristics is obtained. This identified damage, caused by the He+ beam, is attributed to localized interfacial Pb centers and delocalized positive fixed-charges, as surmised from simulations. Comprehension of the long-term interaction and mobility of radiation-induced damage are key for future design of rad-hard devices.

Implementation of an inexpensive cathodoluminescence and electron beam induced current image generator coupled to a scanning electron microscope

In this work, implementation of a novelty cathodoluminescence and electron beam induced current image generator system for do in situ experiments in a scanning electron microscopy (SEM) is presented. The equipment is composed by one mechatronic system (MS) with interchangeable probes and digitalization system programed with Labview. Porous silicon and Eu2(WO4)3 microparticles were characterized in cathodoluminescense mode with luminescence peaks centered at 410 and 613 nm, respectively. For CL imaging, the emission signal is collected through a probe of nine optical fibers and transduced to an electrical signal via a photomultiplier tube (PMT). In other way, the configuration in EBIC mode was tested with commercial silicon monocrystalline solar cell to determine internal defects using a current mapping. However for EBIC imaging, the current is collected by two electrodes connected to a picoammeter synchronized with the electron beam. CL and EBIC images are compared with SE images and chemical elemental mapping images to correlate the emission and defects regions of the sample.

(Invited) Electron Beam Induced Current Microscopy of Interfacial Barrier Effects in Al2O3/TiOx Resistive Switches

Resistive switching devices (ReRAM) represent a broad class of two-terminal continuously tunable resistors including memristors, phase change memory (PCM), valence change memory (VCM), and electrochemical metallization cells (ECM). Though these devices, especially PCM, are increasingly being commercialized by industry for use in next generation memories, they are also all actively studied for use as synaptic weights in next generation hardware-accelerated neuromorphic networks. We have previously investigated Electron Beam Induced Current Microscopy as a means of reliably characterizing resistive switches. In that investigation, we observed surprising electronic effects, such as internal secondary electron emission, in addition to more traditional electron-hole pair separation, and we broke those up into constituent currents based on their origin through Monte-Carlo modeling of the electron beam-matter interaction. Now, armed with a new understanding of the physics of EBIC imaging, we study the impact of manufacturing variations on resistive switches by continuously tuning the thickness of an Al2O3 interfacial barrier. Shifts in the apparent ratios of internal secondary electron emission from the top electrode to the bottom electrode and vice versa appear to indicate a continuous tuning of the apparent filament diameter as both a function of the injected current and the interfacial barrier thickness. This yields an apparent reduction in the current density, the primary effect of which is a reduction in the device damage from forming and a suppression of parasitic leakage currents imaged in devices without interfacial barriers. Figure 1

Scanning TEM EBIC Imaging of Resistive Memory Switching Processes

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Random walk on spheres method for solving drift-diffusion problems

Abstract The well-known random walk on spheres method (RWS) for the Laplace equation is here extended to drift-diffusion problems. First we derive a generalized spherical mean value relation which is an extension of the classical integral mean value relation for the Laplace equation. Next we give a probabilistic interpretation of the kernel. The distribution on the sphere generated by this kernel is then related to the von Mises–Fisher distribution on the sphere which can be efficiently simulated. The rigorous expressions are given for the case of constant velocity drift, but the algorithm is then extended to solve drift-diffusion problems with arbitrary varying drift velocity vector. Applications to cathodoluminescence and EBIC imaging of defects and dislocations in semiconductors are discussed.

Local electrical properties of n-AlInAs/i-GaInAs electron channel structures characterized by theprobe-electron-beam-induced current technique

We developed a probe-electron-beam-induced current (probe-EBIC) technique to investigate the electrical properties of n-Al(0.48)In(0.52)As/i-Ga(0.30)In(0.70)As electron channel structures for a high-electron-mobility transistor, grown on a lattice-matched InP substrate and lattice-mismatched GaAs (001) and Si (001) substrates. EBIC imaging of planar surfaces at low magnifications revealed misfit dislocations originating from the AlInAs-graded buffer layer. The cross-sections of GaInAs channel structures on an InP substrate were studied by high-magnification EBIC imaging as well as cathodoluminescence (CL) spectroscopy. EBIC imaging showed that the structure is nearly defect-free and the carrier depletion zone extends from the channel toward the i-AlInAs buffer layer.

Structure and recombination properties of extended defects in the dislocation slip plane in silicon

AbstractIt is shown, that moving 60° dislocations in Si as well as in SiGe generate high density of extended defects in their slip plane. As a result, the plastic deformation introduces in the crystal volume in addition to the dislocations a very dense system of extended defects, spatially separated from dislocations. The EBIC imaging revealed strong recombination contrast associated with these extended defects. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Electrical and recombination properties and deep traps spectra in MOCVD ELOG GaN layers

AbstractElectrical properties, deep levels spectra, spectra of microcathodoluminescence, diffusion lengths of minority carriers were studied in undoped GaN films grown by standard metallorganic chemical vapour deposition on sapphire and by the epitaxial lateral overgrowth technique (ELOG). It is shown that the total concentrations of shallow donors and of electron and hole traps are very considerably lower in the ELOG material compared to the ordinary MOCVD samples. MCL and electron beam induced current EBIC imaging of ELOG samples suggests that the dislocation density in the overgrown regions is on the order of 106 cm–2 while in‐between these regions it is similar to the dislocation density in the standard material, about 109 cm–2. Local diffusion lengths were shown to follow the same trend as dislocation densities. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

How to improve lateral pn-junction electron detectors for microcolumn systems

Design rules for lateral pn-junction detectors have been established and verified by numerical simulations and measurements of the detector efficiency for different geometries. The test devices were fabricated by diffusion of phosphorus into boron-doped silicon substrates. The efficiency was measured by direct electron irradiation in a scanning electron microscope. EBIC imaging was used to obtain the depletion layer width used for calculating the upper limit of the efficiency for the given geometries. All experimental values agree well with the theoretical predictions. It is demonstrated that the efficiency of lateral pn-junction detectors can be improved without reduction of the bandwidth.

Electrical Characterization of Silicon With Buried Defects

ABSTRACTDepth-dependent electrical characterization of epitaxial silicon extrinsically gettered with intentionally introduced misfit dislocations is described. To study the effect of buried defects on minority carrier lifetime, a modified Zerbst analysis of the MOS capacitance vs. time response was used to determine generation lifetime as a function of space charge region width. In addition, SEMEBIC imaging at different electron beam energies and EBIC imaging of cross-sections were used to investigate the depth-dependent electrical behavior of these materials.

Design and performance of an amplifier for EBIC imaging in a scanning electron microscope

The design of an amplifier with a suitable gain (of the order of 106-108 V A-1) and a 600 kHz bandwidth is described for EBIC imaging within a SEM. The performance is evaluated with some types of specimens (transistors, solar cells) which are often probed by EBIC. This amplifier seems better suited to EBIC applications and may be constructed at far lower cost than some commercially available electrometer amplifiers which appear to be widely used.

Charge-coupled device and charge-injection device imaging

A brief review is given of the advances in solid-state imaging during the last ten years. The issues of surface channel versus buried channel, aliasing versus prefiltering, frame transfer (FT) versus interline transfer (IT) versus charge-injection device (CID), and direct view versus EBIC imaging are discussed. Time-delay-and-integration (TDI) and infrared imaging are discussed. Finally applications are considered.

Charge-coupled device and charge-injection device imaging

A brief review is given of the advances in solid-state imaging during the last ten years. The issues of surface channel versus buried channel, aliasing versus prefiltering, frame transfer (FT) versus interline transfer (IT) versus charge-injection device (CID), and direct view versus EBIC imaging are discussed. Time-delay-and-integration (TDI) and infrared imaging are discussed. Finally applications are considered.