Evaluation of Curvature and Stress in 3C-SiC Grown on Differently Oriented Si Substrates

2011 ◽  
Vol 679-680 ◽  
pp. 137-140 ◽  
Author(s):  
Bernard Enrico Watts ◽  
Giovanni Attolini ◽  
Tullo Besagni ◽  
Matteo Bosi ◽  
Claudio Ferrari ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Raman Spectroscopy ◽  
Tensile Stress ◽  
Mechanical Deformation ◽  
Raman Analysis ◽  
Si Substrates ◽  
Temperature Ramps ◽  
Substrate Curvature

To assess deformation issues in SiC/Si, different pre-growth procedures were investigated, involving the addition of SiH4 to C3H8 during the temperature ramps used for the carbonization. 3C-SiC layers were deposited on (001) and (111) Si substrates by VPE. The mechanical deformation of the wafer was measured by makyoh, obtaining 2D maps of the entire wafers. For the same pre-growth procedures, the substrate curvature depends strongly on the orientation of the substrate, (001) or (111), being generally lower for (111) substrates. The deformation results were compared with XRD and Raman spectroscopy. Plastic deformation of the substrate was evidenced by XRD, while the presence of tensile stress is suggested by Raman analysis.

Residual Stress Measurement in Silicon Substrate After Local Thermal Oxidation Using Microscopic Raman Spectroscopy

1991 ◽  
Vol 226 ◽  
Author(s):  
Hideo Miura ◽  
Hiroshi Sakata ◽  
Shinji Sakata Merl
Keyword(s):  
Residual Stress ◽  
Raman Spectroscopy ◽  
Tensile Stress ◽  
Oxide Film ◽  
Film Thickness ◽  
Silicon Dioxide ◽  
Thermal Oxidation ◽  
Silicon Substrate ◽  
Nitride Film ◽  
Oxide Film Thickness

AbstractThe residual stress in silicon substrates after local thermal oxidation is discussed experimentally using microscopic Raman spectroscopy. The stress distribution in the silicon substrate is determined by three main factors: volume expansion of newly grown silicon–dioxide, deflection of the silicon–nitride film used as an oxidation barrier, and mismatch in thermal expansion coefficients between silicon and silicon dioxide.Tensile stress increases with the increase of oxide film thickness near the surface of the silicon substrate under the oxide film without nitride film on it. The tensile stress is sometimes more than 100 MPa. On the other hand, a complicated stress change is observed near the surface of the silicon substrate under the nitride film. The tensile stress increases initially, as it does in the area without nitride film on it. However, it decreases with the increase of oxide film thickness, then the compressive stress increases in the area up to 170 MPa. This stress change is explained by considering the drastic structural change of the oxide film under the nitride film edge during oxidation.

(n,m) Assignments and quantification for single-walled carbon nanotubes on SiO2/Si substrates by resonant Raman spectroscopy

Nanoscale ◽  
2015 ◽  
Vol 7 (24) ◽  
pp. 10719-10727 ◽  
Author(s):  
Daqi Zhang ◽  
Juan Yang ◽  
Feng Yang ◽  
Ruoming Li ◽  
Meihui Li ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Si Substrates ◽  
Resonant Raman ◽  
Walled Carbon Nanotubes

An ωRBM–dt relation specifically suitable for random SWNTs on SiO2/Si substrates grown by various catalysts.

Raman Spectroscopy of Epitaxial Si/Si1-xGe, xHeterostructures

1998 ◽  
Vol 533 ◽  
Author(s):  
Ran Liu ◽  
Stefan Zollner ◽  
Ming Liaw ◽  
David O'meara ◽  
Nigel Cave
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Treatment ◽  
Raman Scattering ◽  
Buffer Layer ◽  
Excellent Agreement ◽  
Lattice Mismatch ◽  
Theoretical Curve ◽  
Sum Rule ◽  
Si Substrates ◽  
Strain Coefficient

AbstractRaman scattering studies were carried out on epi Si/Si1-xGex (x = 0.1 to 0.3) heterostructures consisting of a thin Si cap layer (100 - 400 A˚), a grade-down Si1-xGex layer, a constant Si1-xGex, buffer layer and a grade-up graded Si1-xGex layer on (100) oriented Si substrates. Different Ge composition, Si1-xGex layer thicknesses and thermal treatment were used to achieve different relaxation in the Si1-xGex layers. It has been revealed that, to a very good approximation, the absolute strains in the cap Si and constant Si1-xGex layers follow a simple sum-rule that is imposed by the lattice mismatch between unstrained Si and completely relaxed Si1-x Gex. This sum rule can be used to determine the Ge composition and stresses in both cap Si and constant Si1-xGex layers. Excellent agreement was found between the theoretical curve obtained with LO phonon strain coefficient b=−930cm−1 and the experimental total strain for all samples, regardless of the degree of the relaxation of the grade-up Si1-xGex layer.

Cu concentration dependence of the mechanical behaviour of Al-Cu alloys

1999 ◽  
Vol 564 ◽  
Author(s):  
J. P. Lokker ◽  
R. S. A. van Winden ◽  
A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Thin Films ◽  
Tensile Stress ◽  
Mechanical Behaviour ◽  
Precipitation Hardening ◽  
Solid Solution Hardening ◽  
Isothermal Hold ◽  
Solution Hardening ◽  
Stress Increase ◽  
Si Substrates ◽  
Cu Alloys

AbstractThis paper reports on the influence of the copper concentration on the mechanical behaviour during thermal cycling and during isothermal holds of Al-Cu thin films on Si substrates. The Cu concentration has been varied in the range between 0 to 1 at.%Upon heating, the films with the larger amount of Cu showed a clear maximum in compressive stress. Moreover, during cooling these samples show a tensile stress increase at the onset precipitation temperature. Further cooling below 200 °C leads to the characteristic tensile stress increase often observed for Al-Cu thin films. An isothermal hold during cooling at 250 °C leads to temporary strengthening of all Al-Cu. The extent of the strengthening is dependent on the Cu concentration and is clearly dependent on the duration of the isothermal hold. Upon further cooling the strengthening disappears and the stress develops according to the original stress temperature dependence. The observations are discussed in terms of solid solution hardening and precipitation hardening.

The Photoluminescence and TEM Studies of Patterned GaAs films on Si Substrate Grown by Molecular Beam Epitaxy

1988 ◽  
Vol 116 ◽  
Author(s):  
Henry P. Lee ◽  
Yi-He Huang ◽  
Xiaoming Liu ◽  
Hong Lin ◽  
John. S. Smith ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Uniaxial Stress ◽  
Luminescence Spectra ◽  
Residual Tensile Stress ◽  
Photoluminescence Intensity ◽  
Patterned Substrate ◽  
Si Substrates ◽  
Gaas Films ◽  
Patterned Films ◽  
Window Area

AbstractPatterned epitaxial GaAs films have been formed on Si substrates by either growth over patterned substrate (selective -area epitaxy) or chemical etching of patterns after growth. The optical properties of these samples are studied by 77K photoluminescence (PL) and the defect structures are investigated by transmission electron microscope (TEM). The patterned substrate consisted of bare Si stripes with width ranging from 10 µm to 100 µm surrounded by Si3N4 films on both sides and a reference area of bare Si. For 1.5 µmiann d 3 µm thick films, PL intensities from the films inside the 10 µm stripe shows 140% and 75% increase over unpatterned areas while the residual tensile stress in the patterned films is very similar to that of the unpatterned area. The increase in the photoluminescence intensity is ascribed to the reduction of crystalline defects inside the the window area. In the chemically etched sample, the pattern consisted of 4 µm by 4 µm squares and 1 mm long stripes with widths ranging from 100 µm to 4 plm. From the shift of PL peaks, a monotonic decrease in the tensile stress versus stripe width is observed. In particular, when the width of the stripe is less than 7 µm. tensile stress becomes essentially uniaxial in agreement with the results obtained by Yacobi et al [16] on a GaAs on InP sample. The polarization of the luminescence spectra parallel and perpendicular to the uniaxial stress of a 4 µm wide stripe agrees well with theoretical prediction. It is also observed that tensile stress is almost completely relieved in the 4 µm by 4 muentc hed squares.

Polycrystalline GeC Thin Films Deposited Using a Unique Hollow Cathode Sputtering Technique

2005 ◽  
Vol 862 ◽  
Author(s):  
R. J. Soukup ◽  
N. J. Ianno ◽  
J. S. Schrader ◽  
V. L. Dalal
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Hollow Cathode ◽  
Growth Conditions ◽  
Group Iv ◽  
Native Oxide ◽  
Cathode Sputtering ◽  
Si Substrates ◽  
New Material ◽  
Equilibrium Growth

AbstractExperimental results on thin films of the new material GexC1-x, deposited by a unique dual plasma hollow cathode sputtering technique are presented. The mostimportant contribution of this work is that it shows that by using non-equilibrium growth conditions resulting from the hollow cathode technique, one can grow Group IV materials which cannot otherwise be grown using normal CVD or MBE processes. The sputtering is accomplished by igniting a dc plasma in the Ar and H2 gases which are fed through Ge and C nozzles.The GeC films are grown on etched Si (100), on Si with the native oxide and on glass. The films grown on glass were quite disordered, but the films grown on both types of Si substrates were very ordered in nature. This order has been characterized using Xray diffraction (XRD) and Raman spectroscopy.Films with as much as 8% C have been deposited. In order to produce useful GexC1-x films, the C must bond to the Ge at lattice sites. Evidence of this desired GeC bond has been seen using Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and XRD.

Raman Spectroscopy for the Analysis of Microplastics in Aquatic Systems

2021 ◽  
pp. 000370282110431
Author(s):  
Veronica Nava ◽  
Maria Luce Frezzotti ◽  
Barbara Leoni
Keyword(s):  
Raman Spectroscopy ◽  
High Spatial Resolution ◽  
Deep Understanding ◽  
R Package ◽  
Aquatic Systems ◽  
Raman Analysis ◽  
Procedural Information ◽  
Chemical Fingerprints ◽  
The Status ◽  
Actual Material

Raman spectroscopy is gaining ground in the analysis of microplastics, especially due to its high spatial resolution that allows the investigation of small plastic particles, whose numeric abundance is argued to be particularly relevant in aquatic systems. Here, we aimed at outlining the status of Raman analysis of microplastics from aquatic systems, highlighting the advantages and the drawbacks of this technique and critically presenting tools and ways to effectively employ this instrument and to improve the spectra obtained and their interpretation. In particular, we summarized procedural information for the use of Raman spectroscopy, and we discussed issues linked to fluorescence interference and the analysis of weathered polymers, which may complicate the interpretation of Raman signatures. In this context, a deep understanding of the different plastic polymers and their Raman peaks and chemical fingerprints is fundamental to avoid misidentification. Therefore, we provided a catalog with detailed information about peaks of most common plastic polymers, and this represents, to the best of our knowledge, the first comprehensive resource that systematically synthesized plastic Raman peaks. Additionally, we focused on plastic additives, which are contained in the majority of plastics. These compounds are often intense in Raman scattering and may partly or completely overlie the actual material types, resulting in the identification of additives alone or misidentification issue. For these reasons, we also presented a new R package “RamanMP” that includes a database of 356 spectra (325 of which are additives). This will help to foster the use of this technique, which is becoming especially relevant in microplastic analysis.

scholarly journals Will Raman meet bacteria on Mars? An overview of the optimal Raman spectroscopic techniques for carotenoid biomarkers detection on mineral backgrounds

2015 ◽  
Vol 95 (2) ◽  
pp. 141-151 ◽  
Author(s):  
J.H. Hooijschuur ◽  
M.F.C. Verkaaik ◽  
G.R. Davies ◽  
F. Ariese
Keyword(s):  
Raman Spectroscopy ◽  
Spectroscopic Techniques ◽  
Time Resolved ◽  
Raman Analysis ◽  
Raman Spectroscopic ◽  
Technical Developments ◽  
Pure Compounds ◽  
Past Life ◽  
Detection Of Biomarkers ◽  
Ideal Technique

AbstractRaman spectroscopy appears to be an ideal technique for the initial detection of biomarkers, molecules that are potentially indicative of life on planetary bodies elsewhere in our solar system. Carotenoids are particularly useful biomarkers as they are used widely across the species, relatively resistant to breakdown and no inorganic source is known. They are used by microorganisms in their cell membranes for protection against UV radiation. In this paper we focus on the detection of carotenoids in microorganisms within a mineral matrix. We compare the Raman signatures of pure compounds with those of laboratory-made mixtures of β-carotene and minerals. Carotenoids covered by 2.5 mm of translucent calcite or 40 mm of transparent halite were detected using a conventional confocal Raman microscope. To improve sensitivity and hence detection levels, Raman measurements were successfully performed under resonant conditions. Raman analysis can be compromised by fluorescence interference. Data are presented to show how the contribution from the fluorescent background in the Raman spectra can be reduced when making use of gated detection in time-resolved Raman spectroscopy. Overall, this study demonstrates some of the potential of Raman spectroscopy as a method for the detection of (past) life signatures during future planetary missions without taking current technical limitations such as instrumental size into account as recent rapid technical developments suggest these limitations will be resolved in time.

Raman spectroscopy of CVD graphene during transfer process from copper to SiO2/Si substrates

2018 ◽  
Vol 6 (1) ◽  
pp. 015601 ◽  
Author(s):  
C Bautista-Flores ◽  
R Y Sato-Berrú ◽  
D Mendoza
Keyword(s):  
Raman Spectroscopy ◽  
Transfer Process ◽  
Cvd Graphene ◽  
Si Substrates

scholarly journals Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1047 ◽  
Author(s):  
Marie Krečmarová ◽  
Daniel Andres-Penares ◽  
Ladislav Fekete ◽  
Petr Ashcheulov ◽  
Alejandro Molina-Sánchez ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Boron Nitride ◽  
Phonon Mode ◽  
Hexagonal Boron Nitride ◽  
Linear Trend ◽  
Thickness Dependence ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Optical Contrast ◽  
Si Substrates

The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two-dimensional semiconductors and semi-metals. However, they have so far not been applied to two-dimensional insulators. In this work, we demonstrate the ability of optical contrast techniques to estimate the thickness of few-layer hBN on SiO2/Si substrates, which was also measured by atomic force microscopy. Optical contrast of hBN on SiO2/Si substrates exhibits a linear trend with the number of hBN monolayers in the few-layer thickness range. We also used bandpass filters (500–650 nm) to improve the effectiveness of the optical contrast methods for thickness estimations. We also investigated the thickness dependence of the high frequency in-plane E2g phonon mode of atomically thin hBN on SiO2/Si substrates by micro-Raman spectroscopy, which exhibits a weak thickness-dependence attributable to the in-plane vibration character of this mode. Ab initio calculations of the Raman active phonon modes of atomically thin free-standing crystals support these results, even if the substrate can reduce the frequency shift of the E2g phonon mode by reducing the hBN thickness. Therefore, the optical contrast method arises as the most suitable and fast technique to estimate the thickness of hBN nanosheets.

Sign in / Sign up

Export Citation Format

Share Document