High Spatial Resolution Mapping of Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
E. Ettedgui ◽  
C. Peng ◽  
L. Tsybeskov ◽  
Y. Gao ◽  
P. M. Fauchet ◽  
...  
Keyword(s):  
Porous Silicon ◽  
High Spatial Resolution ◽  
Growth Conditions ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force ◽  
Resolution Mapping ◽  
Mapping Techniques ◽  
Sectional Analysis

ABSTRACTPorous silicon (PSI) samples with high photoluminescence (PL) efficiency were examined using microscopic mapping techniques including scanning election microscopy (SEM) and spatially resolved photoluminescence (SRPL). Studies of the growth conditions indicate that the homogeneity of the PL and the surface roughness of the sample depend on the preparation procedure of the PSI layer. SEM and spatially-resolved reflectance scans of an n-type sample with a PSI layer on the order of 100 μm reveal a highly fractured surface. SRPL of the same sample shows non uniform PL on a scale of 5 μm. Cross-sectional analysis of the samples with SRPL and SEM reveals the intricate multilayer structure of the PSI film. The top portion of the PSI film is largely responsible for the PL and is composed of isolated column-like structures. We have also observed cross-shaped structures reminiscent of stress fractures on the surface of PSI films using SEM or optical microscopy. Furthermore, atomic force microscopy (AFM) and SEM measurements of the surface of PSI films of intermediate thickness reveal that samples which appear smooth on ̃ lμm scale are actually covered with clumped structures on the order of 100 to 150 nm.

scholarly journals Non-Destructive Characterization of Porous Silicon Using X-Ray Reflectivity

1994 ◽  
Vol 358 ◽  
Author(s):  
E. Chason ◽  
T.R. Guilinger ◽  
M.J. Kelly ◽  
T.J. Headley ◽  
A.J. Howard
Keyword(s):  
Porous Silicon ◽  
Film Growth ◽  
Interface Roughness ◽  
Electrochemical Anodization ◽  
Cross Sectional ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Constant Rate

ABSTRACTUnderstanding the evolution of porous silicon (PS) layers at the early stages of growth is important for determining the mechanism of PS film growth and controlling the film properties. We have used X-ray reflectivity (XRR) to determine the evolution of layer thickness and interfacial roughness during the growth of thin PS layers (< 200 nm) prepared by electrochemical anodization. The porous layer grows at a constant rate for films as thin as 15 nm indicating a very short incubation period during which the surface may be electropolished before the PS structure begins to form. Interface roughness measurements indicate that the top surface of the film remains relatively smooth during growth while the roughness of the PS/silicon interface increases only slightly with film thickness. The XRR results are compared with results obtained from the same films by cross-sectional transmission electron microscopy (XTEM), atomic force microscopy (AFM) and gravimetry.

KINETICS, MICROSTRUCTURE AND STRAIN IN GaN THIN FILMS GROWN VIA PENDEO-EPITAXY

2004 ◽  
Vol 14 (01) ◽  
pp. 21-37
Author(s):  
A. M. ROSKOWSKI ◽  
E. A. PREBLE ◽  
S. EINFELDT ◽  
P. M. MIRAGLIA ◽  
J. SCHUCK ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Growth Conditions ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Microelectronic Devices ◽  
Atomic Force ◽  
Transmission Electron ◽  
Thermal Stability Of

Maskless pendeo-epitaxy involves the lateral and vertical growth of cantilevered "wings" of material from the sidewalls of unmasked etched forms. Gallium Nitride films grown at 1020°C via metalorganic vapor phase epitaxy on GaN / AlN /6 H - SiC (0001) substrates previously etched to form [Formula: see text]-oriented stripes exhibited similar vertical [0001] and lateral [Formula: see text] growth rates, as shown by cross-sectional scanning electron microscopy. Increasing the temperature increased the growth rate in the latter direction due to the higher thermal stability of the [Formula: see text] surface. The [Formula: see text] surface was atomically smooth under all growth conditions with a root mean square (RMS)=0.17 nm. High resolution X-ray diffraction and atomic force microscopy of the pendeo-epitaxial films confirmed transmission electron microscopy results regarding the significant reduction in dislocation density in the wings. This result is important for the properties of both optoelectronic and microelectronic devices fabricated in III-Nitride structures. Measurement of strain indicated that the wing material is crystallographically relaxed as evidenced by the increase in the c-axis lattice parameter and the upward shift of the E2 Raman line frequency. A strong D°X peak at 3.466 eV was also measured in the wing material. However, tilting of the wings of ≤0.15° occurred due to the tensile stresses in the stripes induced by the mismatch in the coefficients of thermal expansion between the GaN and the underlying substrate.

High-Spatial-Resolution Topographic Imaging and Dimer Distance Analysis of Si(100)-(2×1) Using Noncontact Atomic Force Microscopy

2008 ◽  
Vol 47 (7) ◽  
pp. 6085-6087 ◽  
Author(s):  
Daisuke Sawada ◽  
Takashi Namikawa ◽  
Masuhiro Hiragaki ◽  
Yoshiaki Sugimoto ◽  
Masayuki Abe ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Force Microscopy ◽  
Distance Analysis ◽  
Atomic Force ◽  
Topographic Imaging

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

Cross-sectional atomic force microscopy of ZnMgSSe- and BeMgZnSe-based laser diodes

1999 ◽  
Vol 75 (17) ◽  
pp. 2626-2628 ◽  
Author(s):  
A. V. Ankudinov ◽  
A. N. Titkov ◽  
T. V. Shubina ◽  
S. V. Ivanov ◽  
P. S. Kop’ev ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Laser Diodes ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Atomic Force

EFFECT OF ETCHING TIME ON OPTICAL AND MORPHOLOGICAL FEATURES OF N-TYPE POROUS SILICON PREPARED BY PHOTO-ELECTROCHEMICAL METHOD

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Asad A. Thahe ◽  
Noriah Bidin ◽  
Mohammed A. Al-Azawi ◽  
Naser M. Ahmed
Keyword(s):  
Porous Silicon ◽  
Gravimetric Method ◽  
Constant Current ◽  
Etching Time ◽  
Absorption Data ◽  
Time Duration ◽  
Constant Current Density ◽  
Force Microscopy ◽  
Atomic Force ◽  
Structure Properties

Achieving efficient visible photoluminescence from porous-silicon (PSi) is demanding for optoelectronic and solar cells applications. Improving the absorption and emission features of PSi is challenging. Photo-electro-chemical etching assisted formation of PSi layers on n-type (111) silicon (Si) wafers is reported. Samples are prepared at constant current density (~30 mA/cm2) under varying etching times of 10, 15, 20, 25, and 30 min. The influence of etching time duration on the growth morphology and spectral properties are inspected. Room temperature photoluminescence (PL) measurement is performed to determine the optical properties of as-synthesized samples. Sample morphologies are imaged via Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The thickness and porosity of the prepared samples are estimated using the gravimetric method. The emission and absorption data is further used to determine the samples band gap and electronic structure properties. Results and analyzed, interpreted with different mechanisms and compared.  

Cross-sectional observation of NaClO stain-etched Al0.5Ga0.5As/GaAs multilayer by atomic force microscopy

1995 ◽  
Vol 30 (3) ◽  
pp. 678-682 ◽  
Author(s):  
Hee Jeen Kim ◽  
Jae Sung Kim ◽  
Yong Kim ◽  
Moo Sung Kim ◽  
Suk-Ki Min
Keyword(s):  
Atomic Force Microscopy ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Atomic Force

Cross-Sectional Nanoindentation of Alumina Thin Films Deposited by Pulsed Laser Deposition Process

2006 ◽  
Author(s):  
Sudheer Neralla ◽  
Sergey Yarmolenko ◽  
Dhananjay Kumar ◽  
Devdas Pai ◽  
Jag Sankar
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
High Hardness ◽  
Deposition Process ◽  
Laser Deposition ◽  
Cross Sectional ◽  
Adhesion Properties ◽  
Force Microscopy ◽  
Atomic Force

Alumina is a widely used ceramic material due to its high hardness, wear resistance and dielectric properties. The study of phase transformation and its correlation to the mechanical properties of alumina is essential. In this study, interfacial adhesion properties of alumina thin films are studied using cross-sectional nanoindentation (CSN) technique. Alumina thin films are deposited at 200 and 700 °C, on Si (100) substrates with a weak Silica interface, using pulsed laser deposition (PLD) process. Effect of annealing on the surface morphology of the thin films is studied using atomic force microscopy. Xray diffraction studies revealed that alumina thin films are amorphous in nature at 200 °C and polycrystalline with predominant gamma alumina phase at 700 °C.

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