The Wet Etching of CdZnTe Substrates for OMVPE Growth

1992 ◽  
Vol 259 ◽  
Author(s):  
T.W. Chan ◽  
X.J. Bao ◽  
I.H. Oh ◽  
P.J. Sides ◽  
E.I. Ko
Keyword(s):  
Defect Density ◽  
Orange Peel ◽  
Wet Etching ◽  
Organometallic Vapor Phase Epitaxy ◽  
Volume Percent ◽  
Substrate Orientation ◽  
Methanol Solutions ◽  
Bromine Concentration ◽  
Cdte Films ◽  
Cdznte Substrates

ABSTRACTThe etching of CdZnTe substrates by bromine-methanol solutions was studied by chemi-mechanical polishing. Over a bromine concentration of 0.5 to 3.5 volume percent, the etch rates varied linearly with bromine concentration, were independent of substrate orientation, and, within experimental uncertainties, were identical to those for the etching of CdTe. The etched samples were used as substrates for the organometallic vapor phase epitaxy (OMVPE) growth of CdTe in an impinging jet reactor. The bromine concentration used in etching did not affect the growth rate or the morphology of the deposited CdTe films, but a higher defect density was found for the film grown on a substrate with the orange-peel structure.

Organometallic Vapor Phase Lateral Epitaxy of Low Defect Density GaN Layers

1997 ◽  
Vol 482 ◽  
Author(s):  
O. H. Nam ◽  
T. S. Zheleva ◽  
M. D. Bremser ◽  
D. B. Thomson ◽  
R. F. Davis
Keyword(s):  
Vapor Phase ◽  
Defect Density ◽  
Complex Function ◽  
Threading Dislocations ◽  
Organometallic Vapor Phase Epitaxy ◽  
Microstructural Characteristics ◽  
Lateral Epitaxial Overgrowth ◽  
Density Of Dislocations ◽  
Lateral Overgrowth ◽  
Lateral Epitaxy

AbstractLateral epitaxial overgrowth (LEO) of GaN layers has been achieved on 3 μm wide and 7 μm spaced stripe windows contained in SiO2 masks on GaN/AIN/6H-SiC(0001) substrates via organometallic vapor phase epitaxy (OMVPE). The extent and microstructural characteristics of lateral overgrowth were a complex function of stripe orientation, growth temperature and triethylgallium (TEG) flow rate. A high density of threading dislocations, originating from the interface of the underlying GaN with the AIN buffer layer, were contained in the GaN grown in the window regions. The overgrowth regions, by contrast, contained a very low density of dislocations. The second lateral epitaxial overgrowth layers were obtained on the first laterally grown layers by the repetition of SiO2 deposition, lithography and lateral epitaxy.

scholarly journals Lateral epitaxy of low defect density GaN layers via organometallic vapor phase epitaxy

1997 ◽  
Vol 71 (18) ◽  
pp. 2638-2640 ◽  
Author(s):  
Ok-Hyun Nam ◽  
Michael D. Bremser ◽  
Tsvetanka S. Zheleva ◽  
Robert F. Davis
Keyword(s):  
Vapor Phase ◽  
Defect Density ◽  
Vapor Phase Epitaxy ◽  
Organometallic Vapor Phase Epitaxy ◽  
Lateral Epitaxy

CdTe Films Grown on InSb Substrates by Organometallic Epitaxy

1986 ◽  
Vol 90 ◽  
Author(s):  
I. B. Bhat ◽  
N. R. Taskar ◽  
J. Ayers ◽  
K. Patel ◽  
S. K. Ghandhi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Organometallic Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Cdte Films ◽  
Secondary Ion ◽  
Cdte Growth

ABSTRACTCadmium telluride layers were grown on InSb substrates by organometallic vapor phase epitaxy and examined using secondary ion mass spectrometry (SIMS), photoluminescence (Pb) and double crystal x-ray diffraction (DCD). The substrate temperature and the nature of the surface prior to growth are shown to be the most important parameters which influence the quality of CdTe layers. Growth on diethyltelluride (DETe) stabilized InSb substrates resulted in CdTe growth with a misorientation of about 4 minutes of arc with respect to the substrates. On the other hand, the grown layers followed the orientation of the substrates when a dimethylcadmium (DMCd) stabilized InSb was used. Growth at 350°C resulted in the smallest x-ray rocking curve (DCRC) full width at half maximum (FWHM) of about 20 arc seconds.

Carbonization Study of Different Silicon Orientations

2007 ◽  
Vol 556-557 ◽  
pp. 171-174 ◽  
Author(s):  
Andrea Severino ◽  
Corrado Bongiorno ◽  
Stefano Leone ◽  
Marco Mauceri ◽  
Giuseppe Pistone ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Time Dependence ◽  
Wide Temperature Range ◽  
Growth Process ◽  
Defect Density ◽  
Si Substrate ◽  
Tem Analysis ◽  
Substrate Orientation ◽  
Step Growth ◽  
Sic Films

3C-SiC/Si heteroepitaxy is hampered by large mismatches in lattice parameters (19.7%) and thermal expansion coefficient (8%) leading to 3C-SiC films containing high defects density. To reduce the presence of defects, a multi-step growth process in a CVD reactor is used. The aim of the work is to study the effect of carbonization on differently oriented Si surfaces, experiencing a 200°C-wide temperature range in a CVD reactor, to improve the crystalline quality. TEM analysis are carried out to evaluate thickness, crystal orientations and defects of carbonized layers with respect to the time-dependence of the process and to the different orientations of the Si substrate. It will be shown that process-related defects are strictly correlated to the substrate orientation either for size, density, occupied area, shape or thickness. Uniform, flat and crystalline thin SiC films are obtained with a low defect density.

TWO DEFECT-RELATED PHOTOLUMINESCENCE SPECTRA AND CROSS-SECTION TEM OF MBE GROWN CdTe ON (100) InSb

1985 ◽  
Vol 56 ◽  
Author(s):  
Z.C. FENG ◽  
A. MASCARENHAS ◽  
W.J. CHOYKE ◽  
R.F.C. FARROW ◽  
J. GREGGI ◽  
...  
Keyword(s):  
Low Temperature ◽  
Substrate Temperature ◽  
Cross Section ◽  
Defect Density ◽  
Luminescence Spectra ◽  
Photoluminescence Spectra ◽  
Region I ◽  
Cdte Films ◽  
Substrate Temperatures ◽  
Region Ii

AbstractA series of MBE grown CdTe films were grown on (100) InSb substrates. The substrate temperature, Ts, was varied from 170° to 285°C in eleven steps. Low temperature (∿2K) photoluminescence measurements and TEM have been combined to show a strong correlation between defect density and the details of the luminescence spectra. A natural division is obtained for samples grown with substrate temperatures from 285°C to 250°C (Region I) and from 225°C to 170°C (Region II).

Effect of Postdeposition Anneal Conditions on Defect Density of HfO[sub 2] Layers Measured by Wet Etching

2004 ◽  
Vol 151 (11) ◽  
pp. F269 ◽  
Author(s):  
M. Claes ◽  
S. De Gendt ◽  
T. Witters ◽  
V. Kaushik ◽  
T. Conard ◽  
...  
Keyword(s):  
Defect Density ◽  
Wet Etching

Defect investigation of GaN thin films etched by photo-electrochemical and hot wet etching by atomic force and transmission electron microscopy

2001 ◽  
Vol 680 ◽  
Author(s):  
P. Visconti ◽  
K. M. Jones ◽  
M. A. Reshchikov ◽  
R. Cingolani ◽  
H. Morkoç ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Density ◽  
Wet Etching ◽  
Hydride Vapor Phase Epitaxy ◽  
Structural Defects ◽  
Accurate Estimation ◽  
Plan View ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTThe availability of reliable and quick methods to investigate defects in GaN films is of great interest. Photo-electrochemical (PEC), and hot wet etching using both H3PO4 acid and molten KOH have been used to study structural defects in GaN layers grown by hydride vapor phase epitaxy and molecular beam epitaxy. The purpose of this work is to determine whether, and under what conditions, these different methods of investigation are consistent and to get to a more accurate estimation of the defect density. As-grown and etched surfaces were investigated by atomic force microscopy (AFM), and plan-view and cross-sectional transmission electron microscopy (TEM). Free-standing whisker-like features and hexagonal etch pits were formed on the etched sample surfaces by PEC and wet etching, respectively. Using plan-view AFM, we found the density of whiskers (8x108-1×109 cm−2) to be similar to the etch pit densities when etched in both H3PO4 and molten KOH under precise etching conditions. During the wet etching process, a careful balance must be struck to ensure that every defect is delineated, but not overetched to cause merging which would lead to an underestimation of the defect density. Additionally, TEM observations confirmed the dislocation densities obtained by etching, which increased our confidence in the consistency of the methods used.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

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