scholarly journals Detection and Localization of Defects in Monocrystalline Silicon Solar Cell

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
P. Tománek ◽  
P. Škarvada ◽  
R. Macků ◽  
L. Grmela
Keyword(s):  
Solar Cell ◽  
Surface Defects ◽  
Near Field ◽  
Electric Energy ◽  
Optical Methods ◽  
Reverse Bias Voltage ◽  
Field Methods ◽  
Near Surface ◽  
Surface Reflection ◽  
Detection And Localization

Near-surface defects in solar cell wafer have undesirable influence upon device properties, as its efficiency and lifetime. When reverse-bias voltage is applied to the wafer, a magnitude of electric signals from defects can be measured electronically, but the localization of defects is difficult using classical optical far-field methods. Therefore, the paper introduces a novel combination of electric and optical methods showing promise of being useful in detection and localization of defects with resolution of 250 nm using near-field nondestructive characterization techniques. The results of mapped topography, local surface reflection, and local light to electric energy conversion measurement in areas with small defects strongly support the development and further evaluation of the technique.

scholarly journals A SAP-DoA Method for the Localization of Two Buried Objects

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Simone Meschino ◽  
Lara Pajewski ◽  
Giuseppe Schettini
Keyword(s):  
Ground Penetrating Radar ◽  
Near Field ◽  
Dielectric Materials ◽  
Arrival Direction ◽  
Near Surface ◽  
Buried Objects ◽  
Radar Applications ◽  
Ground Penetrating ◽  
Detection And Localization ◽  
Dielectric Objects

A localization technique for buried metallic and dielectric objects is proposed and tested. An array of isotropic antennas investigates a scenario with cylindrical targets buried in a dielectric soil. The targets are in the near field of the array, and a Sub-Array Processing (SAP) approach is adopted: the array is partitioned into subarrays, and Direction of Arrival (DoA) algorithms are used to process the electromagnetic field received by each subarray and estimate the dominant arrival direction of the signal. By triangulating all the estimated DoAs, a crossing pattern is obtained. It is filtered by a Poisson-based procedure and subsequently elaborated by the -means clustering method in order to distinguish between targets and background, estimate the number of targets, and find their position. Several simulations have been performed to compare different DoA algorithms and to test the localization method in the presence of two buried cylinders. Different values of the permittivity of the involved dielectric materials have been considered; the target positions and size have also been varied. The proposed procedure can be useful for ground-penetrating radar applications, near-surface probing, and for the detection and localization of defects in a hosting medium.

scholarly journals A Model-Based Study of Transmit-Receive Longitudinal Arrays for Inspection of Subsurface Defects

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Ehsan Mohseni ◽  
Charles Macleod ◽  
Yashar Javadi ◽  
Randika K. W. Vithanage ◽  
Zhen Qiu ◽  
...  
Keyword(s):  
Surface Defects ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Target Material ◽  
Field Zone ◽  
Flat Bottom ◽  
Near Surface ◽  
Array Configuration ◽  
Surface Areas ◽  
Matrix Arrays

Abstract Dual matrix transmit-receive longitudinal (TRL) arrays have been shown to provide an improved signal to noise ratio in the near field zone which makes them the most suitable array configuration for the inspection of near-surface defects. This study aims to compare the performance of different configurations for transmit-receive longitudinal matrix arrays. For this purpose, four matrix configurations of 2 × 32, 4 × 16, 4 × 32, and 8 × 16 elements are investigated using EXTENDE CIVA modeling package. The array operating frequencies investigated are either 5 MHz or 10 MHz. The effect of different natural focal depths, arrays separation distances, dynamic electronic depth focusing, and electronic beam skewing for these TRL arrays are considered in models prepared in CIVA. The inspection of a series of flat bottom holes extended up to a few millimeters under the surface using the selected TRL configurations is also investigated in the study. It is found that the performance of focusing for near-surface areas is more efficient using the 4 × 16 and 8 × 16 elements configurations as compared with the others, and the signal amplitudes of the defects located deeper in the target material are almost independent of the configuration.

INVESTIGATION OF NEAR-SURFACE DEFECTS INDUCED BY SPIKE RAPID THERMAL ANNEALING IN c-SILICON SOLAR CELLS

2016 ◽  
Vol 23 (02) ◽  
pp. 1550107
Author(s):  
GUODONG LIU ◽  
PAN REN ◽  
DAYONG ZHANG ◽  
WEIPING WANG ◽  
JIANFENG LI
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Surface Defects ◽  
Crystalline Silicon ◽  
Defect Density ◽  
Near Surface ◽  
Si Solar Cell ◽  
Dislocation Defects

The defects induced by a spike rapid thermal annealing (RTA) process in crystalline silicon (c-Si) solar cells were investigated by the photoluminescence (PL) technique and the transmission electron microscopy (TEM), respectively. Dislocation defects were found to form in the near-surface junction region of the monocrystalline Si solar cell after a spike RTA process was performed at 1100[Formula: see text]C. Photo J–V characteristics were measured on the Si solar cell before and after the spike RTA treatments to reveal the effects of defects on the Si cell performances. In addition, the Silvaco device simulation program was used to study the effects of defects density on the cell performances by fitting the experimental data of RTA-treated cells. The results demonstrate that there was an obvious degradation in the Si solar cell performances when the defect density after the spike RTA treatment was above [Formula: see text][Formula: see text]cm[Formula: see text].

Effect of Three-Dimensional Near Surface Defects on Rolling and Sliding Contact Fatigue

1994 ◽  
Vol 116 (4) ◽  
pp. 841-848 ◽  
Author(s):  
M. Liu ◽  
T. N. Farris
Keyword(s):  
Stress Distribution ◽  
Fatigue Limit ◽  
Surface Defects ◽  
Near Field ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
The Body ◽  
Sliding Contact ◽  
Element Formulation ◽  
Near Surface

The effect of three-dimensional defects such as voids and inclusions on the sliding contact subsurface stress distribution and fatigue limit is investigated. Three-dimensional finite-infinite boundary elements are utilized to model the body by discretizing its surface and the interface between the solid and the defect. The multidomain boundary element formulation is employed to accurately model the effect of the inclusion on the stress distribution. It is shown that the void has a greater near field effect on the stress distribution while the effect of a stiff inclusion applies over a larger distance. The critical stress points during a load passage are predicted based on a search of the maximum distortional strain energy. The stresses at the critical points are used for the fatigue limit pressure estimation by incorporating the equivalent stress concept with the Haigh diagram. The model predicts that a near surface spherical void of given size and depth reduces the maximum allowable fatigue limit design pressure by 75 percent while a stiff inclusion of the same size, shape, and location reduces it by 25 percent.

Near-field scanning optical microscopy

1986 ◽  
Vol 44 ◽  
pp. 642-643
Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Visible Radiation ◽  
Field Methods ◽  
Optical Elements ◽  
Optical Region ◽  
Order Of Magnitude ◽  
Nondestructive Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

Electron Channelling Contrast Imaging of Dislocations

1990 ◽  
Vol 48 (1) ◽  
pp. 600-601
Author(s):  
J.T. Czernuszka ◽  
N.J. Long ◽  
P.B. Hirsch
Keyword(s):  
Field Emission ◽  
Secondary Electron ◽  
Surface Defects ◽  
Spot Size ◽  
Beam Divergence ◽  
Contrast Imaging ◽  
Scattered Electron ◽  
Near Surface ◽  
Filter System ◽  
Electron Channelling

In the 1970s there was considerable interest in the development of the electron channelling contrast imaging (ECCI) technique for imaging near surface defects in bulk (electron opaque) specimens. The predictions of the theories were realised experimentally by Morin et al., who used a field emission gun (FEG) operating at 40-50kV and an energy filter such that only electrons which had lost no more than a few 100V were detected. This paper presents the results of a set of preliminary experiments which show that an energy filter system is unneccessary to image and characterise the Burgers vectors of dislocations in bulk specimens. The examples in the paper indicatethe general versatility of the technique.A VG HB501 STEM with a FEG was operated at 100kV. A single tilt cartridge was used in the reflection position of the microscope. A retractable back-scattered electron detector was fitted into the secondary electron port and positioned to within a few millimetres of the specimen. The image was acquired using a Synoptics Synergy framestore and digital scan generator and subsequently processed using Semper 6. The beam divergence with the specimen in this position was 2.5 mrads with a spot size of approximately 4nm. Electron channelling patterns were used to orientate the sample.

Direct Plan View FIB Liftout for Near-Surface Defect Analysis in TEM

2013 ◽  
Author(s):  
Max L. Lifson ◽  
Carla M. Chapman ◽  
D. Philip Pokrinchak ◽  
Phyllis J. Campbell ◽  
Greg S. Chrisman ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Silicon Germanium ◽  
Focused Ion Beam ◽  
Surface Defects ◽  
Ion Beam ◽  
Misfit Dislocations ◽  
Tem Analysis ◽  
Plan View ◽  
Near Surface ◽  
Straightforward Method

Abstract Plan view TEM imaging is a powerful technique for failure analysis and semiconductor process characterization. Sample preparation for near-surface defects requires additional care, as the surface of the sample needs to be protected to avoid unintentionally induced damage. This paper demonstrates a straightforward method to create plan view samples in a dual beam focused ion beam (FIB) for TEM studies of near-surface defects, such as misfit dislocations in heteroepitaxial growths. Results show that misfit dislocations are easily imaged in bright-field TEM and STEM for silicon-germanium epitaxial growth. Since FIB tools are ubiquitous in semiconductor failure analysis labs today, the plan view method presented provides a quick to implement, fast, consistent, and straightforward method of generating samples for TEM analysis. While this technique has been optimized for near-surface defects, it can be used with any application requiring plan view TEM analysis.

Reemitted positron spectroscopy of near-surface defects

1990 ◽  
Vol 42 (4) ◽  
pp. 1910-1916 ◽  
Author(s):  
T. McMullen ◽  
M. J. Stott
Keyword(s):  
Surface Defects ◽  
Near Surface ◽  
Positron Spectroscopy
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