Structural characterization of defects in EFG- and HVPE-grown β-Ga2O3 crystals

Author(s):  
Osamu Ueda ◽  
Makoto Kasu ◽  
Hirotaka Yamaguchi

Abstract This paper reviews the status of characterization of defects in β-Ga2O3 crystals grown by edge-defined film-fed growth and hydride vapor phase epitaxy using chemical etching, scanning electron microscopy, focused ion beam scanning ion microscopy, X-ray topography (XRT), and transmission electron microscopy (TEM). The observed defects are classified into four types: dislocations, stacking faults (SFs), twins, and plate-like nanovoids (PNVs). First, we present the detailed characterization of dislocations in the crystal by chemical etching, XRT, and TEM, and discuss possible slip systems. Next, we describe XRT analyses of two types of SFs: SFs 1 lying on the (2 ̅01) plane and SFs 2 on the (111) and (11 ̅1) planes. We describe the results for twins found in crystals via high-resolution TEM and electron diffraction analysis, and PNVs corresponding to etch pits on the (010) plane. Finally, we discuss possible generation mechanisms of the defects and their influence on device characteristics.

2002 ◽  
Vol 738 ◽  
Author(s):  
Heinz D. Wanzenboeck ◽  
Stefan Harasek ◽  
Wolfgang Brezna ◽  
Alois Lugstein ◽  
Helmut Langfischer ◽  
...  

ABSTRACTImaging critical features by using transmission electron microscopy (TEM) or scanning electron microscopy (SEM) provides a versatile approach for nanostructure characterization. The combination of focused ion beam (FIB) technology for exposing defective sites beneath the surface is shown. Reliability testing and defect analysis by localized characterization of multilayered structures is demonstrated. TEM-imaging of a transistor gate with a locally confined radiation damage demonstrates target preparation by FIB yielding high-resolution TEM samples. The TEM imaging requires a longer sample preparation but provides high image quality (TEM). Investigation of materials previously processed with FIB revealed amorphization damage by the high energetic Ga-ion beam. This damage layer with a thickness in the range of 50 to 100 nm was confirmed in simulation. This disadvantageous damage by amorphization originating from FIB preparation of the cross-section could be removed by soft sputtering with a 250 V Ar+ ion beam. This combined method using FIB for microsample preparation and TEM for imaging and analysis was proven to be a powerful tool the exploitation of nanostructured devices and for defect analysis on a highly localized scale.


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 717 ◽  
Author(s):  
Wenbo Xin ◽  
Joseph Severino ◽  
Arie Venkert ◽  
Hang Yu ◽  
Daniel Knorr ◽  
...  

In this report, networks of carbon nanotubes (CNTs) are transformed into composite yarns by infusion, mechanical consolidation and polymerization of dicyclopentadiene (DCPD). The microstructures of the CNT yarn and its composite are characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and a focused ion beam used for cross-sectioning. Pristine yarns have tensile strength, modulus and elongation at failure of 0.8 GPa, 14 GPa and 14.0%, respectively. In the composite yarn, these values are significantly enhanced to 1.2 GPa, 68 GPa and 3.4%, respectively. Owing to the consolidation and alignment improvement, its electrical conductivity was increased from 1.0 × 105 S/m (raw yarn) to 5.0 × 105 S/m and 5.3 × 105 S/m for twisted yarn and composite yarn, respectively. The strengthening mechanism is attributed to the binding of the DCPD polymer, which acts as a capstan and increases frictional forces within the nanotube bundles, making it more difficult to pull them apart.


2009 ◽  
Vol 15 (S2) ◽  
pp. 368-369 ◽  
Author(s):  
S Duarte ◽  
A Avishai ◽  
A Sadan

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


Nanoscale ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 5304-5316 ◽  
Author(s):  
Jessi E. S. van der Hoeven ◽  
Ernest B. van der Wee ◽  
D. A. Matthijs de Winter ◽  
Michiel Hermes ◽  
Yang Liu ◽  
...  

Focused ion beam-scanning electron microscopy tomography for quantitative real space studies of particle assemblies on a single particle level.


2012 ◽  
Vol 18 (S2) ◽  
pp. 614-615
Author(s):  
J. Lin ◽  
W. Heeschen ◽  
J. Reffner ◽  
J. Hook

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.


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