Demonstration of 3C-SiC MEMS Structures on Polysilicon-on-oxide Substrates

2010 ◽  
Vol 1246 ◽  
Author(s):  
Christopher Locke ◽  
Christopher Frewin ◽  
Luca Abbati ◽  
Stephen E. Saddow
Keyword(s):  
Strain Relaxation ◽  
Chemical Properties ◽  
Sem Analysis ◽  
Film Stress ◽  
Si Substrate ◽  
Bridge Structures ◽  
Oxide Substrate ◽  
The Impact ◽  
Sic Film ◽  
Sic Films

AbstractSilicon carbide has robust mechanical, electrical, and chemical properties which make it an attractive material candidate for micro- and nano-electromechanical systems (MEMS and NEMS). 3C-SiC films grown via a polysilicon seed-layer CVD-deposited on an oxide coated (111) Si substrate offers an innovative method to overcome the residual film stress issues associated with 3C-SiC heteroepitaxy and the difficulties of fabricating structures from 3C-SiC films. The oxide plays a dual role by permitting film relaxation with respect to the supporting substrate and functioning as a MEMS release layer, allowing MEMS structures such as cantilevers and diaphragms, to be easily fabricated from the 3C-SiC film. The impact of the oxide layer on the relaxation of the film stress was investigated by comparing direction-sensitive MEMS stress sensors fabricated from 3C-SiC films grown via a polysilicon-on-oxide-coated-substrate and a polysilicon-on-crystalline Si substrate. Scanning Electron Microscopy (SEM) analysis of bridge structures fabricated on the polysilicon-on-oxide substrate revealed evidence of film strain relaxation when compared to bridge structures fabricated on the polysilicon-on-crystalline Si substrate. However, the upward-curled cantilever and comb structures fabricated on both substrates indicate the presence of a strain gradient in the 3C-SiC film grown on both substrates.

Conversion of single crystal Si(100) to SiC film by C2H2

1993 ◽  
Vol 8 (3) ◽  
pp. 535-544 ◽  
Author(s):  
Chien C. Chiu ◽  
Seshu B. Desu
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Smooth Surface ◽  
Reaction Times ◽  
Si Substrate ◽  
Etch Pits ◽  
X Ray ◽  
Sic Film ◽  
Sic Films ◽  
Scanning Electron

SiC thin films grown from the reaction between acetylene (C2H2) and the Si(100) substrates in a horizontal hot-wall CVD reactor by different procedures were studied using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The growth of the SiC films was observed from the behavior of Si2p peaks and their plasmons. A SiC thin film with a thickness of 35 Å and having a smooth surface morphology was obtained in C2H2 diluted by H2 at 1050 °C for a period of 60 min. Etch pits and hillocks were observed with increasing reaction time at 1050 °C. For the conversion conducted in C2H2, but in the absence of H2, a SiC monolayer with smooth morphology was obtained at 950 °C for 7 min and defects were observed for longer reaction times at this temperature. Defects were also observed for reaction times as short as 10 s at higher reaction temperatures (e.g., 1000 °C). H2 seems to play a key role in suppressing the formation of defects and the reaction between C2H2 and Si substrate. The formation of defects was correlated to the out-diffusion of Si in the carbonization process.

scholarly journals 3C-SiC Films on Si for MEMS Applications: Mechanical Properties

2009 ◽  
Vol 615-617 ◽  
pp. 633-636 ◽  
Author(s):  
Christopher Locke ◽  
G. Kravchenko ◽  
P. Waters ◽  
J. D. Reddy ◽  
K. Du ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Small Degree ◽  
Film Stress ◽  
Si Substrate ◽  
Plastic Properties ◽  
Si Substrates ◽  
High Residual Stress ◽  
Mems Cantilevers ◽  
Sic Films

Single crystal 3C-SiC films were grown on (100) and (111) Si substrate orientations in order to study the resulting mechanical properties of this material. In addition, poly-crystalline 3C-SiC was also grown on (100)Si so that a comparison with monocrystaline 3C-SiC, also grown on (100)Si, could be made. The mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates were measured by means of nanoindentation using a Berkovich diamond tip. These results indicate that polycrystalline SiC thin films are attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging. MEMS cantilevers and membranes fabricated from a 2 µm thick single crystal 3C-SiC grown on (100)Si under similar conditions resulted in a small degree of bow with only 9 µm of deflection for a cantilever of 700 µm length with an estimated tensile film stress of 300 MPa. Single crystal 3C-SiC films on (111)Si substrates have the highest elastic and plastic properties, although due to high residual stress they tend to crack and delaminate.

High-Rate Rotated Epitaxy of 3C-SiC(111) on Si(110) Substrate for Qualified Epitaxial Graphene on Silicon

2013 ◽  
Vol 740-742 ◽  
pp. 327-330 ◽  
Author(s):  
Maki Suemitsu ◽  
Shota Sanbonsuge ◽  
Eiji Saito ◽  
Myung Ho Jung ◽  
Hirokazu Fukidome ◽  
...  
Keyword(s):  
Epitaxial Graphene ◽  
The Other ◽  
High Rate ◽  
Si Substrate ◽  
High Quality ◽  
Si Substrates ◽  
Growth Method ◽  
Step Growth ◽  
Sic Film ◽  
Sic Films

In the formation of epitaxial graphene on Si substrates, the growth of high-quality 3C-SiC thin films on Si substrates is a key to success. As a solution to the large mismatch between the Si substrate and the 3C-SiC film, rotated epitaxy in which 3C-SiC(111) films are grown on Si(110) substrates is quite attractive. In some applications, on the other hand, a certatin thickness (~100 nm or more) is required for this 3C-SiC films as well. A two-step growth method has been thus developed to realize a high-rate, qualified rotated epitaxy. A qualified graphene is found to be formed on this rotated epi-film, as typified by the increase of the grain size by a factor of 1.6 from the non-rotated epitaxy.

Defect-induced strain relaxation in 3C-SiC films grown on a (100) Si substrate at low temperature in one step

CrystEngComm ◽  
2016 ◽  
Vol 18 (36) ◽  
pp. 6817-6823 ◽  
Author(s):  
Bing Yang ◽  
Hao Zhuang ◽  
Junhao Li ◽  
Nan Huang ◽  
Lusheng Liu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Strain Relaxation ◽  
Si Substrate ◽  
One Step ◽  
Sic Films

scholarly journals The Impact of Combination of Ozonation and Ultrasonication Process on Morphological and Chemical Properties of κ-Carrageenan

REAKTOR ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 49-53
Author(s):  
Nurfiningsih Nurfiningsih ◽  
Ratnawati Ratnawati ◽  
Aji Prasetyaningrum
Keyword(s):  
Molecular Weight ◽  
Chemical Properties ◽  
Morphological Characteristics ◽  
Weight Fraction ◽  
Sem Analysis ◽  
Low Molecular Weight ◽  
Sulfate Content ◽  
Biomedical Field ◽  
The Impact ◽  
And Chemical Properties

Carrageenan application in the biomedical field is influenced by the size of molecular weight. Depolymerization process is needed for changing the high molecular weight (HMW) fraction of κ- carrageenan into low molecular weight fraction (LMW) of κ- carrageenan. Ozone is a powerful oxidant and considered for depolymerization of κ- carrageenan. This research was conducted as an investigation on the influence of the combination of ozonation and ultrasonication (OZ/US) on the chemical and morphological characteristics of κ-carrageenan. FTIR and Scanning electron microscopy (SEM) was used to determine the change of chemical and morphological characteristics of κ-carrageenan. The result of this study showed that there was no change of chemical properties of κ-carrageenan during OZ/US treatment. The sulfate content was obtained after OZ/US treatment tends to be stable.  Nevertheless, the result of SEM analysis showed that there were changes on morphological characteristics of κ-carrageenan after OZ/US treatment.  Keywords: ultrasonication, κ-carrageenan, ozonation, morphological, chemical

scholarly journals The Impact of Filler Geometry on Polylactic Acid-Based Sustainable Polymer Composites

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 149
Author(s):  
Karol Leluk ◽  
Stanisław Frąckowiak ◽  
Joanna Ludwiczak ◽  
Tomasz Rydzkowski ◽  
Vijay Kumar Thakur
Keyword(s):  
Polymer Composites ◽  
Polylactic Acid ◽  
Matrix Material ◽  
Chemical Properties ◽  
Precipitated Calcium Carbonate ◽  
Cellulose Fibres ◽  
Shape Factors ◽  
Pure Cellulose ◽  
Physico Chemical ◽  
The Impact

Recently, biocomposites have emerged as materials of great interest to the scientists and industry around the globe. Among various polymers, polylactic acid (PLA) is a popular matrix material with high potential for advanced applications. Various particulate materials and nanoparticles have been used as the filler in PLA based matrix. One of the extensively studied filler is cellulose. However, cellulose fibres, due to their hydrophilic nature, are difficult to blend with a hydrophobic polymer matrix. This leads to agglomeration and creates voids, reducing the mechanical strength of the resulting composite. Moreover, the role of the various forms of pure cellulose and its particle shape factors has not been analyzed in most of the current literature. Therefore, in this work, materials of various shapes and shape factors were selected as fillers for the production of polymer composites using Polylactic acid as a matrix to fill this knowledge gap. In particular, pure cellulose fibres (three types with different elongation coefficient) and two mineral nanocomponents: precipitated calcium carbonate and montmorillonite were used. The composites were prepared by a melt blending process using two different levels of fillers: 5% and 30%. Then, the analysis of their thermomechanical and physico-chemical properties was carried out. The obtained results were presented graphically and discussed in terms of their shape and degree of filling.

scholarly journals Assessment of Pellets from Three Forest Species: From Raw Material to End Use

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 447
Author(s):  
Miguel Alfonso Quiñones-Reveles ◽  
Víctor Manuel Ruiz-García ◽  
Sarai Ramos-Vargas ◽  
Benedicto Vargas-Larreta ◽  
Omar Masera-Cerutti ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Ash Content ◽  
Hot Water ◽  
Raw Material ◽  
Chemical Components ◽  
Energy Yield ◽  
Cellulose Content ◽  
Fixed Carbon ◽  
End Use ◽  
The Impact

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. & Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p < 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.

The influence of Hanok experience on tourists’ attitude and behavioral intention: An interplay between experiences and a Value-Attitude-Behavior model

2021 ◽  
pp. 135676672110117
Author(s):  
Choong-Ki Lee ◽  
Yvette Reisinger ◽  
Muhammad Shakil Ahmad ◽  
Yae-Na Park ◽  
Choong-Won Kang
Keyword(s):  
Behavioral Intention ◽  
Sem Analysis ◽  
Experience Economy ◽  
A Value ◽  
Functional Value ◽  
Experienced Utility ◽  
Attitude Behavior ◽  
Tourism And Hospitality ◽  
The Impact ◽  
Value Functional

This study examines the impact of Hanok experience on tourists’ attitude and behavioral intention using the experience economy ( Pine and Gilmore, 1998 ) and the experienced utility theory ( Kahneman et al., 1997 ). Specifically, the study explores how tourists’ experiences are associated with a Value-Attitude-Behavior (VAB) model in the context of a heritage tourism attraction such as Jeonju Hanok Village in South Korea. A total of 323 responses were examined using SEM analysis. The results revealed that educational, entertainment, and escapism experiences significantly influenced functional value. Functional value had a significant relationship with attitude, which was positively related to behavioral intention. The results indicate the interplay of tourists’ experiences with the VAB model. The study provides theoretical and practical implications for tourism and hospitality academics and practitioners.

scholarly journals The impact of orally administered gadolinium orthovanadate GdVO4:Eu3+ nanoparticles on the state of phospholipid bilayer of erythrocytes

2020 ◽  
Vol 45 (4) ◽  
pp. 389-395
Author(s):  
Anton Tkachenko ◽  
Anatolii Onishchenko ◽  
Vladimir Klochkov ◽  
Nataliya Kavok ◽  
Oksana Nakonechna ◽  
...  
Keyword(s):  
Fluorescent Probes ◽  
Lipid Membranes ◽  
Chemical Properties ◽  
Proton Donor ◽  
The State ◽  
Phospholipid Bilayer ◽  
Erythrocyte Membranes ◽  
Control Group ◽  
Donor Ability ◽  
The Impact

AbstractObjectivesTo assess the state of phospholipid bilayer of red blood cells (RBCs) in rats orally exposed to gadolinium orthovanadate GdVO4:Eu3+ nanoparticles (VNPs) during two weeks using fluorescent probes − ortho-hydroxy derivatives of 2,5-diaryl-1,3-oxazole.MethodsSteady-state fluorescence spectroscopy: a study by the environment-sensitive fluorescent probes − 2-(2′-OH-phenyl)-5-phenyl-1,3-oxazole (probe O1O) and 2-(2′-OH-phenyl)-phenanthro[9,10]-1,3-oxazole (probe PH7).ResultsNo significant changes are detected in the spectra of the fluorescent probes bound to the RBCs from the rats orally exposed to nanoparticles in comparison with the corresponding spectra of the probes bound to the cells from the control group of animals. This indicates that, in case of the rats orally exposed to nanoparticles, no noticeable changes in physico-chemical properties (i.e., in the polarity and the proton-donor ability) are observed in the lipid membranes of RBCs in the region, where the probes locate.ConclusionsNo changes in the physical and chemical properties of the erythrocyte membranes are detected in the region from glycerol backbones of phospholipids to the center of the phospholipid bilayer in the rats orally exposed to VNPs during 2 weeks.

scholarly journals Impact of Carcinogenic Chromium on the Cellular Response to Proteotoxic Stress

2019 ◽  
Vol 20 (19) ◽  
pp. 4901 ◽  
Author(s):  
Leonardo M. R. Ferreira ◽  
Teresa Cunha-Oliveira ◽  
Margarida C. Sobral ◽  
Patrícia L. Abreu ◽  
Maria Carmen Alpoim ◽  
...  
Keyword(s):  
Stress Response ◽  
Health Effects ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Chemical Properties ◽  
Adverse Health Effects ◽  
Proteotoxic Stress ◽  
Adverse Health ◽  
The Impact

Worldwide, several million workers are employed in the various chromium (Cr) industries. These workers may suffer from a variety of adverse health effects produced by dusts, mists and fumes containing Cr in the hexavalent oxidation state, Cr(VI). Of major importance, occupational exposure to Cr(VI) compounds has been firmly associated with the development of lung cancer. Counterintuitively, Cr(VI) is mostly unreactive towards most biomolecules, including nucleic acids. However, its intracellular reduction produces several species that react extensively with biomolecules. The diversity and chemical versatility of these species add great complexity to the study of the molecular mechanisms underlying Cr(VI) toxicity and carcinogenicity. As a consequence, these mechanisms are still poorly understood, in spite of intensive research efforts. Here, we discuss the impact of Cr(VI) on the stress response—an intricate cellular system against proteotoxic stress which is increasingly viewed as playing a critical role in carcinogenesis. This discussion is preceded by information regarding applications, chemical properties and adverse health effects of Cr(VI). A summary of our current understanding of cancer initiation, promotion and progression is also provided, followed by a brief description of the stress response and its links to cancer and by an overview of potential molecular mechanisms of Cr(VI) carcinogenicity.

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