scholarly journals Coincident Electron Channeling and Cathodoluminescence Studies of Threading Dislocations in GaN

2013 ◽  
Vol 20 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Gunasekar Naresh-Kumar ◽  
Jochen Bruckbauer ◽  
Paul R. Edwards ◽  
Simon Kraeusel ◽  
Ben Hourahine ◽  
...  
Keyword(s):  
Structural Damage ◽  
Light Emission ◽  
Threading Dislocations ◽  
Nonradiative Recombination ◽  
Contrast Imaging ◽  
Force Microscopy ◽  
Electron Channeling ◽  
Microscopy Techniques ◽  
Cathodoluminescence Imaging ◽  
Edge Dislocations

AbstractWe combine two scanning electron microscopy techniques to investigate the influence of dislocations on the light emission from nitride semiconductors. Combining electron channeling contrast imaging and cathodoluminescence imaging enables both the structural and luminescence properties of a sample to be investigated without structural damage to the sample. The electron channeling contrast image is very sensitive to distortions of the crystal lattice, resulting in individual threading dislocations appearing as spots with black–white contrast. Dislocations giving rise to nonradiative recombination are observed as black spots in the cathodoluminescence image. Comparison of the images from exactly the same micron-scale region of a sample demonstrates a one-to-one correlation between the presence of single threading dislocations and resolved dark spots in the cathodoluminescence image. In addition, we have also obtained an atomic force microscopy image from the same region of the sample, which confirms that both pure edge dislocations and those with a screw component (i.e., screw and mixed dislocations) act as nonradiative recombination centers for the Si-doped c-plane GaN thin film investigated.

Low Energy Electron Channeling Contrast Imaging from 4H-SiC Surface by SEM and its Comparison with CDIC-OM and PL Imaging

2017 ◽  
Vol 897 ◽  
pp. 193-196
Author(s):  
Koji Ashida ◽  
Toru Aiso ◽  
Manabu Okamoto ◽  
Hirokazu Seki ◽  
Makoto Kitabatake ◽  
...  
Keyword(s):  
Etching Rate ◽  
Optical Microscope ◽  
Low Energy ◽  
Energy Electron ◽  
Contrast Imaging ◽  
Force Microscopy ◽  
Electron Channeling ◽  
Wafer Inspection ◽  
Low Energy Electron ◽  
The One

Low energy electron channeling contrast imaging (LE-ECCI) by scanning electron microscopy (SEM) was adopted to evaluate both the direction and length of the topmost hexagonal stacking sequence of the Si–C bilayers on 4H-SiC (0001). LE-ECCI revealed the change in the dangling bond configuration at step edges depending on SiC thermal etching rate, which was difficult to be detected by optical microscope (OM) and even by atomic force microscopy (AFM). Furthermore, LE-ECCI was applied to evaluate the atomic structure of polytype inclusions in commercially available 3-inch diameter 4o off-axis 4H-SiC (0001) epitaxial wafer. The validity of LE-ECCI was discussed by comparing the one with two kinds of widely used wafer inspection methods: confocal OM with differential interference contrast (CDIC-OM) and photoluminescence (PL) imaging.

scholarly journals Using Multiple Contrast Mechanisms via Forescatter Electron Channeling Contrast Imaging to Resolve the Burgers Vector of GaN Threading Dislocations

2009 ◽  
Vol 15 (S2) ◽  
pp. 674-675
Author(s):  
YN Picard ◽  
ME Twigg ◽  
JD Caldwell ◽  
CR Eddy Jr. ◽  
MA Mastro ◽  
...  
Keyword(s):  
Threading Dislocations ◽  
Contrast Imaging ◽  
Burgers Vector ◽  
Electron Channeling ◽  
Contrast Mechanisms

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Diffraction Contrast of Threading Dislocations in GaN and 4H-SiC Epitaxial Layers Using Electron Channeling Contrast Imaging

2010 ◽  
Vol 39 (6) ◽  
pp. 743-746 ◽  
Author(s):  
M. E. Twigg ◽  
Y. N. Picard ◽  
J. D. Caldwell ◽  
C. R. Eddy ◽  
M. A. Mastro ◽  
...  
Keyword(s):  
Epitaxial Layers ◽  
Threading Dislocations ◽  
Contrast Imaging ◽  
Electron Channeling ◽  
Diffraction Contrast

Electron channeling contrast imaging of atomic steps and threading dislocations in 4H-SiC

2007 ◽  
Vol 90 (23) ◽  
pp. 234101 ◽  
Author(s):  
Y. N. Picard ◽  
M. E. Twigg ◽  
J. D. Caldwell ◽  
C. R. Eddy ◽  
P. G. Neudeck ◽  
...  
Keyword(s):  
Threading Dislocations ◽  
Contrast Imaging ◽  
Atomic Steps ◽  
Electron Channeling

Modifications of Defects Concentration Induced by Ammonia Flow Rate and its Effects on Gallium Nitride Grown by MOCVD

2009 ◽  
Vol 1195 ◽  
Author(s):  
Suresh Sundaram ◽  
Vattikondala Ganesh ◽  
Thirugnanam Prem Kumar ◽  
Manavaimaran Balaji ◽  
Vedachala Iyer Ganesan ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Positron Beam ◽  
Growth Conditions ◽  
Molar Ratio ◽  
Threading Dislocations ◽  
Oxygen Impurity ◽  
Force Microscopy ◽  
Mocvd Growth ◽  
Schottky Device ◽  
Edge Dislocations

AbstractOptical and schottky diode characteristics of unintentionally doped GaN films grown by MOCVD were reported. GaN epilayers were grown with different V/III ratio by varying the source ammonia (NH3) flowrate. It exhibit changes in the density of threading dislocations (TDs) and reduced carbon and oxygen impurity incorporation. The density of dislocations determined from hot-wet chemical etching and atomic force microscopy show that on decreasing the ammonia flowrate, threading dislocations decreases. Low energy positron beam was employed to study the Ga vacancies in the epilayers. S-parameter vs. positron beam energy curves clearly shows increase in SL on increasing the V/III ratio indicating that the point defects trapping positron increases. Corroborative HRXRD, Photoluminescence and Hall measurements confirm the reduction in trapping defects and threading edge dislocations with reducing V/III molar ratio. The effects of such variation of compensating centres and radiative centres as a function of MOCVD growth conditions on optical properties and schottky device characteristics like radiative decay lifetime, barrier height and reverse leakage current respectively were discussed.

scholarly journals Micropyramid Vertical Ultraviolet GaN/AlGaN Multiple Quantum Wells LEDs on Si(111)

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Yuebo Liu ◽  
Honghui Liu ◽  
Hang Yang ◽  
Wanqing Yao ◽  
Fengge Wang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Leakage Current ◽  
Light Emission ◽  
Uv Light ◽  
Multiple Quantum ◽  
Threading Dislocations ◽  
Nonradiative Recombination ◽  
Small Current ◽  
Uv Led ◽  
Optical Output

Micropyramid vertical GaN-based ultraviolet (UV) light-emitting diodes (LEDs) on Si(111) substrate have been fabricated by selective area growth to reduce threading dislocations and the polarization effects. There is no-light emission at the bottom and six planes of the pyramid at lower current due to the leakage current and nonradiative recombination of the dislocation at the bottom and the 90° threading dislocations (TDs) at six planes of the pyramid, and the top of the pyramid is the high-brightness region. The micropyramid UV LED has a high optical output intensity under a small current injection, and the series resistance of unit area is only a quarter of the conventional vertical LEDs, so the micropyramid UV LED would have a high output power under the drive circuit. The reverse leakage current of a single micropyramid UV LED is 2 nA at −10 V.

Simulation of Forescattered Electron Channeling Contrast Imaging of Threading Dislocations Penetrating SiC Surfaces

2008 ◽  
Vol 1068 ◽  
Author(s):  
Mark E. Twigg ◽  
Yoosuf N. Picard ◽  
Joshua D. Caldwell ◽  
Charles R. Eddy ◽  
Philip G. Neudeck ◽  
...  
Keyword(s):  
Primary Source ◽  
Threading Dislocations ◽  
Contrast Imaging ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
Image Intensity ◽  
Electron Channeling ◽  
Kikuchi Line ◽  
Simulated Images

ABSTRACTThe interpretation of ECCI images in the forescattered geometry presents a more complex diffraction configuration than that encountered in the backscattered geometry. Determining the Kikuchi line that is the primary source of image intensity often requires more than simple inspection of the electron-channeling pattern. This problem can be addressed, however, by comparing recorded ECCI images of threading screw dislocations in 4H-SiC with simulated images. An ECCI image of this dislocation is found to give the orientation of the dominant Kikuchi line, greatly simplifying the determination of the diffraction simulation. In addition, computed images of threading screw dislocations in 4H-SiC were found to exhibit channeling contrast essentially identical to that obtained experimentally by ECCI and allowing determination of the dislocation Burgers vector.

Nondestructive analysis of threading dislocations in GaN by electron channeling contrast imaging

2007 ◽  
Vol 91 (9) ◽  
pp. 094106 ◽  
Author(s):  
Y. N. Picard ◽  
J. D. Caldwell ◽  
M. E. Twigg ◽  
C. R. Eddy ◽  
M. A. Mastro ◽  
...  
Keyword(s):  
Threading Dislocations ◽  
Nondestructive Analysis ◽  
Contrast Imaging ◽  
Electron Channeling

Fault Isolation of MOL and FEOL Buried Defects Using Conductive Atomic Force Microscopy as a Complement to Passive Voltage Contrast Imaging

2017 ◽  
Author(s):  
Lucile C. Teague Sheridan ◽  
Linda Conohan ◽  
Chong Khiam Oh
Keyword(s):  
Atomic Force Microscopy ◽  
Cmos Technology ◽  
Fault Isolation ◽  
Contrast Imaging ◽  
Conductive Atomic Force Microscopy ◽  
Isolation Technique ◽  
Conductive Afm ◽  
Force Microscopy ◽  
Atomic Force ◽  
Voltage Contrast

Abstract Atomic force microscopy (AFM) methods have provided a wealth of knowledge into the topographic, electrical, mechanical, magnetic, and electrochemical properties of surfaces and materials at the micro- and nanoscale over the last several decades. More specifically, the application of conductive AFM (CAFM) techniques for failure analysis can provide a simultaneous view of the conductivity and topographic properties of the patterned features. As CMOS technology progresses to smaller and smaller devices, the benefits of CAFM techniques have become apparent [1-3]. Herein, we review several cases in which CAFM has been utilized as a fault-isolation technique to detect middle of line (MOL) and front end of line (FEOL) buried defects in 20nm technologies and beyond.

Case Studies in Atomic Force Probe Analysis

2006 ◽  
Author(s):  
Randal Mulder ◽  
Sam Subramanian ◽  
Tony Chrastecky
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Light Emission ◽  
Electrical Characterization ◽  
Logic Circuits ◽  
Contrast Imaging ◽  
Atomic Force ◽  
Measuring Surface ◽  
Analysis Environment

Abstract The use of atomic force probe (AFP) analysis in the analysis of semiconductor devices is expanding from its initial purpose of solely characterizing CMOS transistors at the contact level with a parametric analyzer. Other uses found for the AFP include the full electrical characterization of failing SRAM bit cells, current contrast imaging of SOI transistors, measuring surface roughness, the probing of metallization layers to measure leakages, and use with other tools, such as light emission, to quickly localize and identify defects in logic circuits. This paper presents several case studies in regards to these activities and their results. These case studies demonstrate the versatility of the AFP. The needs and demands of the failure analysis environment have quickly expanded its use. These expanded capabilities make the AFP more valuable for the failure analysis community.

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