scholarly journals Thermal Activation of Crystalline Silicon Ions in Alkaline Solution

1970 ◽  
Vol 7 (7) ◽  
pp. 15-18
Author(s):  
Shobha Kanta Lamichhane
Keyword(s):  
Activation Energy ◽  
Etch Rate ◽  
Thermal Activation ◽  
Crystalline Silicon ◽  
Micro Electro Mechanical System ◽  
Alkaline Solutions ◽  
Force Microscopy ◽  
Microstructure Fabrication ◽  
Atomic Force ◽  
Key Techniques

Anisotropic wet chemical etching of silicon in alkaline solutions (KOH) is one of the key techniques for the manufacture of microstructure. Fabrication of Micro-electro mechanical system (MEMS) part demand smooth surface finish and angular dependent etch rate. The absolute values of orientation dependent etch rate is found to vary with thermal agitation. In this work, experimental results of etch rate is found with their unusual values of activation energy along different planes. The various sites that an atom can occupy are not equivalent of their energy; some are more favorable to removal than others. In this paper attention is being given to demonstrate thermal activation is the prime factor that influences the behavior of etching mechanism as well as surface morphology. Atomic force microscopy (AFM) has been employed to analyze the morphology of the etched silicon surface at relevant elevated temperature. A systematic variation in morphological growth leads to stabilized surface structure under the influence of associated activation energy. Keywords: Activation energy; Etching; Anisotropy; Etch rate; MEMS; LPCVD; SOI. DOI: 10.3126/sw.v7i7.3817 Scientific World Vol.7(7) 2009 pp.15-18

scholarly journals Thermal Induced Microstructures of KOH Etched Silicon Surface

1970 ◽  
Vol 5 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Shobha Kanta Lamichhane
Keyword(s):  
Activation Energy ◽  
Silicon Surface ◽  
Etch Rate ◽  
Low Voltage ◽  
Micro Electro Mechanical System ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Engineering And Technology ◽  
Etched Silicon

Anisotropic KOH etching of silicon for the fabrication of Micro-electro mechanical system (MEMS) part is based on surface finish and angular dependence of etch rate, creating thin diaphragm. The absolute values of orientation dependent etch rate is found to vary with thermal agitation. In this work, experimental results of etch rate is found quite consistent with simulated and are justify with their unusual values of activation energy along different planes. The various sites that an atom can occupy are not equivalent of their energy; some are more favorable to removal than others. In this paper attention is given to demonstrate thermal activation energy is the prime parameter that influences the behavior of etching mechanism as well as AFM surface morphology. Low-voltage contact mode atomic force microscopy (AFM) has been employed to analyze the morphology of the etched silicon surface at relevant different temperature. A systematic variation in morphological growth leads to stabilized surface structure under the influence of associated activation energy is concluded. Key words: Etching; Anisotropy; Etch rate; diaphragm; MEMS; LPCVD; SOI; AFM DOI: 10.3126/kuset.v5i1.2847 Kathmandu University Journal of Science, Engineering and Technology Vol.5, No.1, January 2009, pp 62-70

scholarly journals Effect of Stabilizer on Gold Leaching with Thiourea in Alkaline Solutions

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 89
Author(s):  
Wenjuan Li ◽  
He Shang ◽  
He Zhou ◽  
Yongsheng Song ◽  
Shuilin Zheng ◽  
...  
Keyword(s):  
Activation Energy ◽  
Sodium Silicate ◽  
Cyclic Voltammetry Curve ◽  
Sodium Sulfite ◽  
Alkaline Solutions ◽  
Gold Leaching ◽  
Force Microscopy ◽  
Atomic Force ◽  
Alkaline Thiourea ◽  
The Stability

The present work investigated the comparison of the effects of Na2SO3 and Na2SiO3 on thiourea stabilization, and a systematic study was undertaken to establish the effects of these stabilizers on the stability of alkaline thiourea, both qualitatively and quantitatively. The effects of these stabilizers on the activation energy of alkaline thiourea gold leaching was also studied. The results showed that sodium silicate was more suitable as a stabilizer in this system than sodium sulfite because the peak current of gold dissolution with sodium sulfite was higher than that with sodium silicate, but the inhibition of thiourea decomposition by the former was less obvious than that of sodium silicate in the cyclic voltammetry curve. The quartz crystal microbalance results showed that the quality decreased to about 100 ng cm2 in the presence of a stabilizer, while it increased to 300 ng cm2 in the absence of the stabilizer. It is inferred that gold can be dissolved by alkaline thiourea in the presence of a stabilizer, while it cannot without a stabilizer because of the decomposition of thiourea. This assumption was confirmed by atomic force microscopy measurements. The surface activation energy of Au dissolution decreased from 183.76 to 98.07 kJ/moL with the addition of sodium silicate, indicating that Au dissolution was promoted with the chemical.

Thermally Induced Activation Energy of Crystalline Silicon in Alkaline Solution

1970 ◽  
Vol 11 ◽  
pp. 215-222
Author(s):  
SK Lamichhane
Keyword(s):  
Activation Energy ◽  
Potassium Hydroxide ◽  
Etch Rate ◽  
Crystalline Silicon ◽  
Lattice Parameter ◽  
Device Fabrication ◽  
Strong Anisotropy ◽  
Temperature Dependent ◽  
Thermal Agitation ◽  
Thermally Induced

Etching of crystalline silicon by potassium hydroxide (KOH) etchant with temperature variation has been studied. Results presented here are temperature dependent ER (etch rate) along the crystallographic orientations. Etching and activation energy are found to be consistently favorable with the thermal agitation for a given crystal plane. Study demonstrates that the contribution of microscopic activation energy effectively controls the etching process. Such a strong anisotropy in ER on KOH allows us a precious control of lateral dimensions of the silicon microstructure as well as surface growth of the crystal during micro device fabrication. Key words: anisotropy; activation energy; etch rate; lattice parameter; micromachining DOI: 10.3126/njst.v11i0.4148Nepal Journal of Science and Technology 11 (2010) 215-222

scholarly journals Dynamic nanoindentation by instrumented nanoindentation and force microscopy: a comparative review

2013 ◽  
Vol 4 ◽  
pp. 815-833 ◽  
Author(s):  
Sidney R Cohen ◽  
Estelle Kalfon-Cohen
Keyword(s):  
Atomic Force Microscopy ◽  
Time And Space ◽  
Material Response ◽  
Force Microscopy ◽  
Atomic Force ◽  
Important Phenomenon ◽  
Comparative Review ◽  
Key Techniques ◽  
Dynamic Nanoindentation

Viscoelasticity is a complex yet important phenomenon that drives material response at different scales of time and space. Burgeoning interest in nanoscale dynamic material mechanics has driven, and been driven by two key techniques: instrumented nanoindentation and atomic force microscopy. This review provides an overview of fundamental principles in nanoindentation, and compares and contrasts these two techniques as they are used for characterization of viscoelastic processes at the nanoscale.

Measurement of bulk etch rate of CR-39 with atomic force microscopy

1998 ◽  
Vol 142 (1-2) ◽  
pp. 111-116 ◽  
Author(s):  
N. Yasuda ◽  
M. Yamamoto ◽  
N. Miyahara ◽  
N. Ishigure ◽  
T. Kanai ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Etch Rate ◽  
Force Microscopy ◽  
Bulk Etch Rate ◽  
Atomic Force

scholarly journals Experimental investigation on anisotropic surface properties of crystalline silicon

BIBECHANA ◽  
2012 ◽  
Vol 8 ◽  
pp. 59-66
Author(s):  
Shobha Kanta Lamichhane
Keyword(s):  
Activation Energy ◽  
Potassium Hydroxide ◽  
Etch Rate ◽  
Crystalline Silicon ◽  
Etching Rate ◽  
Energy Concentration ◽  
Temperature Dependent ◽  
Thermal Agitation ◽  
Anisotropic Surface ◽  
Experimental Values

Anisotropic etching of silicon has been studied by wet potassium hydroxide (KOH) etchant with its variation of temperature and concentration. Results presented here are temperature dependent etch rate along the crystallographic orientations. The etching rate of the (111) surface family is of prime importance for microfabrication. However, the experimental values of the corresponding etch rate are often scattered and the etching mechanism of (111) remains unclear. Etching and activation energy are found to be consistently favorable with the thermal agitation for a given crystal plane. Study demonstrate that the contribution of microscopic activation energy that effectively controls the etching process. Such a strong anisotropy in KOH allows us a precious control of lateral dimensions of the silicon microstructure.Keywords: microfabrication; activation energy; concentration; anisotropy; crystal planeDOI: http://dx.doi.org/10.3126/bibechana.v8i0.4828  BIBECHANA 8 (2012) 59-66  

scholarly journals Thermal Induced Conductance of KOH Etched Silicon Surface

1970 ◽  
Vol 6 (1) ◽  
pp. 79-88
Author(s):  
Shobha Kanta Lamichhane
Keyword(s):  
Silicon Surface ◽  
Etch Rate ◽  
Thermal Activation ◽  
Energy Gap ◽  
Low Voltage ◽  
Thermal Agitation ◽  
Force Microscopy ◽  
Etching Mechanism ◽  
Engineering And Technology ◽  
Etched Silicon

Anisotropic KOH etch rate of silicon is found to vary with thermal agitation along withcrystal plane orientation. In this work, experimental results of etch rate is found with theirunusual values of activation energy along different planes. The various sites that an atomcan occupy are not equivalent of their energy; some are more favorable to removal thanothers. In this paper attention is given to demonstrate thermal activation influences thebehavior of etching mechanism as well as surface morphology. Low-voltage contact modeatomic force microscopy (AFM) has been employed to analyze the morphology of theetched silicon surface at relevant temperature. With temperature evolution the width of theforbidden energy gap is going down and hence conductivity is rises.Keywords: Anisotropy; Etch rate; MEMS; SOI; AFM; Contact mode.DOI: 10.3126/kuset.v6i1.3314 Kathmandu University Journal of Science, Engineering and Technology Vol.6(1) 2010, pp79-88

Electroplated CuO Thin Films from High Alkaline Solutions

2011 ◽  
Vol 15 (1) ◽  
pp. 49-55
Author(s):  
V. Dhanasekaran ◽  
T. Mahalingam ◽  
S. Rajendran ◽  
Jin Koo Rhee ◽  
D. Eapen
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Film Thickness ◽  
Structural Characteristics ◽  
Band Gap Energy ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Microstructural Parameters ◽  
Atomic Force

CuO thin films were coated on ITO substrates by an electrodeposition route through potentiostatic mode. The electrodeposited CuO thin films were characterized and the role of copper sulphate concentration on the structural, morphological and optical properties of the CuO films was studied. Film thickness was measured by a stylus profilometer and found to be in the range between 800 and 1400 nm. The structural characteristics studies were carried out using X-ray diffraction and found that the films are polycrystalline in nature with a cubic structure. The preferential orientation of CuO thin films is found to be along (111) plane. The estimated microstructural parameters revealed that the crystallite size increases whereas the number of crystallites per unit area decreases with increasing film thickness. SEM studies show that the grain sizes of CuO thin films vary between 100 and 150 nm and also morphologies revealed that the electrodeposited CuO exhibits uniformity in size and shape. The surface roughness is estimated 15 nm of the CuO film were studied by atomic force microscopy. Optical properties of the films were analyzed from absorption and transmittance studies. The optical band gap energy was determined to be 1.5 eV from absorption coefficient. The variation of refractive index (n), extinction coefficient (k), with wavelength was studied and the results are discussed.

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