scholarly journals Fabrication of Sio2-based microcantilevers by anisotropic chemical etching of (100) single crystal Si

2007 ◽  
Vol 72 (11) ◽  
pp. 1127-1138 ◽  
Author(s):  
Vesna Jovic ◽  
Jelena Lamovec ◽  
Mirjana Popovic ◽  
Zarko Lazic
Keyword(s):  
Aqueous Solution ◽  
Single Crystal ◽  
Silicon Substrate ◽  
Chemical Etching ◽  
Si Substrate ◽  
Si Wafer

The undercutting process of thermal SiO2 microcantilevers with different orientations on (100) Si wafer was studied. The silicon substrate was removed by anisotropic chemical etching with a 25 wt. % aqueous solution of TMAH or a 30 wt. % aqueous KOH solution at 80 ?C. It was found that [110] oriented cantilevers were undercutting frontally along the length and [100] oriented cantilevers experience undercutting along the width of the cantilever, which is a less time consuming process. The studies showed that the [100] orientation of SiO2 microbridges enables theirs fabrication on a (100) oriented Si substrate.

Effect of Wheel Additive On Chemo-Mechanical Grinding (CMG) of Single Crystal Si Wafer

2010 ◽  
Vol 447-448 ◽  
pp. 106-110 ◽  
Author(s):  
H. Takahashi ◽  
Y.B. Tian ◽  
Y. Mikami ◽  
J. Shimizu ◽  
Li Bo Zhou ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Single Crystal ◽  
Sodium Carbonate ◽  
Low Cost ◽  
The Other ◽  
Si Substrate ◽  
Mechanical Grinding ◽  
Different Types ◽  
Selection Of ◽  
Si Wafer

Chemo-mechanical grinding (CMG) process is a promising process for large-sized Si substrate fabrication at low cost. However, effect of additive in CMG wheel is not completely understood yet. In this paper, three different CMG wheels were developed, in which one excluded additive and the other two contained two kinds of additive i.e. silicon dioxide and sodium carbonate. Grinding experiments were conducted to explore the influence of exclusion of additive and inclusion of different kinds of additive on CMG performance. The grinding characteristics of the three wheels were also analyzed and discussed to reveal the roles of wheel compositions in CMG process. This work provides some fundamental insights for the selection of different types of additive for optimization of CMG wheel.

scholarly journals Effect of Small Doses of Gamma Radiation on the Optical Properties of Nanostructured Silicon Obtained by Metal-Stimulated Chemical Etching in situ

2020 ◽  
Vol 20 (4) ◽  
pp. 288-298
Author(s):  
Olga Ya. Belobrovaya ◽  
◽  
Victor V. Galushka ◽  
Victoria S. Ismailova ◽  
Valentina P. Polyanskaya ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Porous Silicon ◽  
Radiation Dose ◽  
Single Crystal ◽  
Chemical Etching ◽  
Total Reflection ◽  
In Situ Monitoring ◽  
Main Peak ◽  
Small Doses

Background and Objectives: Porous silicon nanowires (SiNP) obtained by the method of metal stimulated chemical etching (EE method) are of great interest. The physical properties of this material depend significantly on the morphology of the nanostructures and their sizes. Given in the literature data on the effect of small doses of ionizing radiation on metals and alloys and the effect of irradiation on the properties of porous silicon and SiNP, makes sense to modify not only the substrate, but also the SiNP layer during its formation by irradiation. A change in the morphology of the formed layers with increasing in situ irradiation within small doses can affect the properties of SiNP. In the literature known to us, this issue is not considered. This work presents studies of the total reflection, Raman scattering, and photoluminescence of SiNP upon irradiation with γ-rays directly in the production process (in situ). Materials and Methods: The formation of nanoporous silicon structures was performed on non-irradiated and irradiated with small doses of gamma-quanta substrates. The substrates were processed by the Saratov State University’s betatron electron brake accelerator at a maximum energy of Eymax ~ 25 MeV. The radiation dose was 30 and 40 kR. A layer of porous SiNP nanosilicon was formed on irradiated and non-irradiated substrates. Samples were obtained by water-based non-electric etching or metal-stimulated chemical etching. The method of chemical etching EE is based on the replacement of silicon when reducing Ag+ → Agо on the surface of the silicon substrate using Ag in an aqueous solution of AgNO3. Porous silicon structures were formed by a two-stage method on irradiated gamma-quanta and non-irradiated p-type silicon substrates with a resistivity of 4.5 Ω cm, oriented in the plane <111>. The substrate was lowered into an aqueous solution of 0.01 M AgNO3 and 5M HF for 60 s., then was etched in an aqueous solution of 5M HF, 0.5 M H2O2 for 20, 40 and 60 minutes, respectively. The studied nanoporous structures were obtained on irradiated and non-irradiated substrates without irradiation and when irradiated in situ with inhibitory gamma radiation of the medical linear electron accelerator Varian Unique of State Health Institution “Regional Clinical Oncology Dispensary” at an electron energy of 6 MeV. After receiving the samples, they were purified in concentrated nitric acid for an hour. The structural properties of SiNP were studied using measurements on an analytical complex based on the Mira 2 LMU scanning electron microscope, as well as the DRON-4 diffractometer using an x-ray tube with a copper anode (Cu-Ka). Full reflection spectra in the range of 500–1100 nm were obtained using a LOMO SF-56 spectrophotometer equipped with a special integrating set-top box. Raman spectra were recorded using a Renishaw inVia spectrometer. Results: The samples under study are quasiordered ensembles of silicon nanowires oriented almost normal to the substrate. The thickness of the SiNP layer is of the order of 1–8 μm, depending on the preparation conditions, and the diameter of the nanowires was 30–400 nm. In all SiNP samples, a decrease in total reflection was observed in the wavelength range of 400–1000 nm as compared to a single-crystal substrate, which is associated with light scattering on an inhomogeneous structural surface. At the initial stage of the process, the defective state of the substrate was decisive; microstresses on the substrate disappear when it is irradiated. For SiNP samples, total reflection increased with increasing radiation dose over time (from 0 to 24 kR) due to improved surface quality, reduced scattering, and a change in layer thickness. In addition, in situ monitoring of SiNP samples indicates the influence of not only the radiation dose of the formed layer on the reflection value, but also the dose of preliminary irradiation of the substrate. Raman spectra were studied to determine the effect of gamma-irradiation on the properties of porous silicon – SiNP in situ. The intensity of the main peak of Raman scattering of SiNP samples obtained on non-irradiated and irradiated substrates is significantly higher compared to the intensity of the main peak characteristic of single-crystal silicon. Against the background of the high Raman signal, light scattering from particles with broken bonds does not appear and basically gives a maximum – a peak P1 of the order of 519.5 cm-1, slightly shifted to the low-frequency region relative to the maximum of peak P1 of a single-crystal silicon substrate 520 cm-1. An increase in the irradiation dose of the substrate leads to an increase in the intensity of the main Raman peak. Studies of Raman spectroscopy of nanostructured porous silicon-silver layers have revealed the effect of surface giant signal amplification (SERS). The maximum silver content is below the surface of the samples. The depth of the silver-enriched layer is about 250– 400 nm. The photoluminescence peak of SiNP samples formed on irradiated and non- irradiated substrates shifts to the shortwavelength region as the radiation dose increases. The shift is much more dependent on the dose of the substrate than on the irradiation of the layer. The calculated nanocrystallite size by λmax was about 2 nm. Conclusion: The results of an experimental study of the optical properties of porous Si structures obtained by metal-stimulated chemical etching when irradiated with small doses of gamma-quanta directly during in situ formation are presented. In situ monitoring of samples indicates the influence not only of the radiation dose of the resulting layer on the value of total reflection, but also the dose of pre-irradiation of the substrate. Studies of Raman spectroscopy of nanostructured layers of “porous silicon-silver” revealed the effect of surface giant signal amplification in samples. There is a shift in the wavelength of the maximum photoluminescence from 600 nm to 750 nm when the irradiation of the substrate changes from 0 to 40 kR at the same radiation dose of the layer.

scholarly journals Effect of Photoillumination on Gold-Nanoparticle-Assisted Chemical Etching of Silicon

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Ming-Hua Shiao ◽  
Chou-Pu Lai ◽  
Bo-Huei Liao ◽  
Yung-Sheng Lin
Keyword(s):  
Chemical Etching ◽  
Substrate Surface ◽  
Lag Time ◽  
Localized Surface Plasmon ◽  
Etching Time ◽  
Galvanic Replacement ◽  
Si Substrate ◽  
Replacement Reaction ◽  
Aspect Ratios ◽  
Si Wafer

Metal-assisted chemical etching (MacEtch) has attracted considerable attention for its ability to fabricate micro- and nanostructures with high aspect ratios and its applications in other microelectromechanical fields. However, few studies have reported the effect of photoillumination on MacEtch. In this study, gold nanoparticles (GNPs) were deposited on the surface of a Si wafer by using the fluoride-assisted galvanic replacement reaction, and then, the effect of photoillumination on the MacEtch of the Si wafer was investigated. The etched depth increased linearly with etching time from 0–45 min and was considerably larger in the illuminated area than the nonilluminated area. A lag time was observed for the MacEtch of the nonilluminated area. However, no lag time was observed in the illuminated area. The trapping of light by the GNPs on the Si substrate surface during the MacEtch process enhanced the etching efficiency due to localized surface plasmon resonance.

Effects of Sodium Carbonate and Ceria Concentration on Chemo-Mechanical Grinding of Single Crystal Si Wafer

2009 ◽  
Vol 76-78 ◽  
pp. 428-433 ◽  
Author(s):  
H. Takahashi ◽  
Y.B. Tian ◽  
J. Sasaki ◽  
Jun Shimizu ◽  
Li Bo Zhou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Sodium Carbonate ◽  
Low Cost ◽  
Wafer Surface ◽  
Si Substrate ◽  
Mechanical Grinding ◽  
Grinding Performance ◽  
Si Wafer

Chemo-mechanical grinding (CMG) process is a promising process for large-sized Si substrate fabrication at low cost. An encountered issue in current CMG process of Silicon (Si) wafers is metallic contaminations on ground Si wafer surface, which is attributed to the existence of sodium carbonate in wheel compounds. In this paper, four different CMG wheels were developed and grinding experiments were conducted to study the effects of exclusion of sodium carbonate and concentration of ceria abrasive on grinding performance. The grinding characteristics of the four wheels were analysized and discussed to reveal the effects of different compositions.

The observation of defects on (100) CdTe surfaces by chemical etching

1992 ◽  
Vol 50 (2) ◽  
pp. 1424-1425
Author(s):  
M.E. Lee
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Chemical Etching ◽  
Crystalline Perfection ◽  
Crystalline Defects ◽  
High Incidence ◽  
Crystallographic Defects ◽  
Cdznte Substrates ◽  
Device Technology

The crystalline perfection of bulk CdTe substrates plays an important role in their use in infrared device technology. The application of chemical etchants to determine crystal polarity or the density and distribution of crystallographic defects in (100) CdTe is not well understood. The lack of data on (100) CdTe surfaces is a result of the apparent difficulty in growing (100) CdTe single crystal substrates which is caused by a high incidence of twinning. Many etchants have been reported to predict polarity on one or both (111) CdTe planes but are considered to be unsuitable as defect etchants. An etchant reported recently has been considered to be a true defect etchant for CdTe, MCT and CdZnTe substrates. This etchant has been reported to reveal crystalline defects such as dislocations, grain boundaries and inclusions in (110) and (111) CdTe. In this study the effect of this new etchant on (100) CdTe surfaces is investigated.The single crystals used in this study were (100) CdTe as-cut slices (1mm thickness) from Bridgman-grown ingots.

scholarly journals Formation and Evaluation of Silicon Substrate with Highly-Doped Porous Si Layers Formed by Metal-Assisted Chemical Etching

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yijie Li ◽  
Nguyen Van Toan ◽  
Zhuqing Wang ◽  
Khairul Fadzli Bin Samat ◽  
Takahito Ono
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Contact Resistance ◽  
Power Factor ◽  
Chemical Etching ◽  
Porous Si ◽  
Si Substrate ◽  
Si Substrates ◽  
Output Performance ◽  
Metal Assisted Chemical Etching

AbstractPorous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact between porous Si and metal is one reason for the reduction of electrical conductivity. In this paper, p- and n-type porous Si were formed on Si substrate by metal-assisted chemical etching. To decrease contact resistance, p- and n-type spin on dopants are employed to dope an impurity element into p- and n-type porous Si surface, respectively. Compared to the Si substrate with undoped porous samples, ohmic contact can be obtained, and the electrical conductivity of doped p- and n-type porous Si can be improved to 1160 and 1390 S/m, respectively. Compared with the Si substrate, the special contact resistances for the doped p- and n-type porous Si layer decreases to 1.35 and 1.16 mΩ/cm2, respectively, by increasing the carrier concentration. However, the increase of the carrier concentration induces the decline of the Seebeck coefficient for p- and n-type Si substrates with doped porous Si samples to 491 and 480 μV/K, respectively. Power factor is related to the Seebeck coefficient and electrical conductivity of thermoelectric material, which is one vital factor that evaluates its output performance. Therefore, even though the Seebeck coefficient values of Si substrates with doped porous Si samples decrease, the doped porous Si layer can improve the power factor compared to undoped samples due to the enhancement of electrical conductivity, which facilitates its development for thermoelectric application.

Fabrication of InP/SiO2/Si Substrate using Ion-Cutting Process and Selective Chemical Etching

2019 ◽  
Vol 6 (1) ◽  
pp. 99-103
Author(s):  
Peng Chen ◽  
Dapeng Xu ◽  
Luke Mawst ◽  
Kimmo Henttinen ◽  
Tommi Suni ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Cutting Process ◽  
Si Substrate ◽  
Selective Chemical ◽  
Selective Chemical Etching

Atomic layer wear of single‐crystal calcite in aqueous solution using scanning force microscopy

1996 ◽  
Vol 80 (5) ◽  
pp. 2680-2686 ◽  
Author(s):  
Nam‐Seok Park ◽  
Myoung‐Won Kim ◽  
S. C. Langford ◽  
J. T. Dickinson
Keyword(s):  
Aqueous Solution ◽  
Single Crystal ◽  
Atomic Layer ◽  
Scanning Force Microscopy ◽  
Force Microscopy ◽  
Scanning Force

Micro- and Nanotextured Silicon for Antireflective Coatings of Solar Cells

2016 ◽  
Vol 39 ◽  
pp. 89-95 ◽  
Author(s):  
Anatoly Druzhinin ◽  
Valery Yerokhov ◽  
Stepan Nichkalo ◽  
Yevhen Berezhanskyi
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
Silicon Substrate ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Silicon Surfaces ◽  
Antireflective Coatings ◽  
High Conversion Efficiency ◽  
Industrial Use

The paper deals with obtaining of textured silicon surfaces by chemical etching. As a result of experiments based on the modification and optimization of obtaining a textured silicon, several methods of chemical texturing of the crystalline silicon surface were developed. It was shown that modified isotropic and anisotropic etching methods are applicable to create a microrelief on the surface of silicon substrate. These methods in addition to their high conversion efficiency can be used for both mono- and multicrystalline silicon which would ensure their industrial use.

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