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.

Novel Miniature DMFC With Monolithic Si Electrodes

2009 ◽  
Author(s):  
Masanori Hayase ◽  
Yosuke Saito
Keyword(s):  
Metal Layer ◽  
Catalyst Layer ◽  
Pt Catalyst ◽  
Galvanic Replacement ◽  
Porous Si ◽  
Si Substrate ◽  
Catalyst Layers ◽  
Novel Structure ◽  
Si Wafer ◽  
Immersion Plating

A through-chip porous Ru-Pt catalyst layer was fabricated on a Si wafer and a novel miniature DMFC (Direct Methanol Fuel Cell) was realized. Recently, we found that porous noble metal layer can be synthesized on Si substrate by immersion plating on a porous Si. In order to realize a DMFC with our novel structure, a porous Ru layer was synthesized on the Si substrate using the immersion plating on the porous Si, then Pt was deposited by galvanic replacement reaction on the porous Ru. The porous Ru-Pt structure showed catalytic activity on methanol oxidization. A through-chip porous Ru-Pt layer was fabricated on a Si wafer by plasma etching and monolithic electrodes with catalyst layers and fuel channels were realized. A preliminary DMFC prototype successfully demonstrated power generation of 2mW/cm2.

scholarly journals Enhanced Surface Properties of Light-Trapping Si Nanowires Using Synergetic Effects of Metal-Assisted and Anisotropic Chemical Etchings

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Youngsoon Jeong ◽  
Chanwoo Hong ◽  
Yeong Hun Jung ◽  
Rashida Akter ◽  
Hana Yoon ◽  
...  
Keyword(s):  
Interfacial Energy ◽  
Chemical Etching ◽  
Low Cost ◽  
Light Trapping ◽  
Si Nanowires ◽  
Si Substrate ◽  
Large Area ◽  
Aspect Ratios ◽  
Energy States ◽  
Si Nanostructures

Abstract Metal-assisted chemical etching (MACE) has been widely explored for developing silicon (Si)-based energy and optical devices with its benefits for low-cost and large-area fabrication of Si nanostructures of high aspect ratios. Surface structures and properties of Si nanostructures fabricated through MACE are significantly affected by experimental and environmental conditions of etchings. Herein, we showed that surfaces and interfacial energy states of fabricated Si nanowires can be critically affected by oxidants of MACE etching solutions. Surfaces of fabricated Si nanowires are porous and their tips are fully covered with lots of Si nano-sized grains. Strongly increased photoluminescence (PL) intensities, compared to that of the crystalline Si substrate, are observed for MACE-fabricated Si nanowires due to interfacial energy states of Si and SiOx of Si nano-sized grains. These Si grains can be completely removed from the nanowires by an additional etching process of the anisotropic chemical etching (ACE) of Si to taper the nanowires and enhance light trapping of the nanowires. Compared with the MACE-fabricated Si nanowires, ACE-fabricated tapered Si nanowires have similar Raman and PL spectra to those of the crystalline Si substrate, indicating the successful removal of Si grains from the nanowire surfaces by the ACE process.

Study of Super Hydrophobic Films on Pre-Sensitized Plate Aluminium Substrate

2012 ◽  
Vol 200 ◽  
pp. 427-429
Author(s):  
Zhuang Liu ◽  
Lin Zhu ◽  
Jing Lin ◽  
Zhi Hui Sun
Keyword(s):  
Contact Angle ◽  
Rough Surface ◽  
Chemical Etching ◽  
Substrate Surface ◽  
Acid Etching ◽  
Etching Time ◽  
Hydrophobic Property ◽  
Aluminium Substrate ◽  
Simple Chemical ◽  
Etched Surface

A simple chemical etching method was developed for corrosion of the pre-sensitized plate aluminium substrate in order to be a rough surface. After the chemical etched surface was treated with fluorination, the pre-sensitized (PS) plate aluminium (Al) substrate surface exhibits a super-hydrophobic property. The effects of the etching time and the etchant concentration on the super-hydrophobici were investigated, and the results show the contact angle of hydrofluoric firstly increases then reduce with acid etching time increasing, and the optimum etching time is 12 min; the contact angle of hydrofluoric firstly increases then reduce with acid etchant concentration increasing, and the optimum etchant concentration is 3 mol /L. When the contact angle increases, the droplet and solid surface tension increases. Film base fine structure of the rough surface is the key to the formation of hydrophobic.

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.

Backside Mechanical Preparation Methodology for Effective Failure Analysis on Small and Non-Exposed Die Paddle Package

2018 ◽  
Author(s):  
Ong Pei Hoon ◽  
Ng Kiong Kay ◽  
Gwee Hoon Yen
Keyword(s):  
Failure Analysis ◽  
Chemical Etching ◽  
Chemical Resistance ◽  
Etching Time ◽  
Lead Frame ◽  
Front Side ◽  
Electrical Measurements ◽  
Mechanical Preparation ◽  
Die Surface ◽  
Copper Lead

Abstract Chemical etching is commonly used in exposing the die surface from die front-side and die backside because of its quick etching time, burr-free and stress-free. However, this technique is risky when performing copper lead frame etching during backside preparation on small and non-exposed die paddle package. The drawback of this technique is that the copper leads will be over etched by 65% Acid Nitric Fuming even though the device’s leads are protected by chemical resistance tape. Consequently, the device is not able to proceed to any other further electrical measurements. Therefore, we introduced mechanical preparation as an alternative solution to replace the existing procedure. With the new method, we are able to ensure the copper leads are intact for the electrical measurements to improve the effectiveness and accuracy of physical failure analysis.

scholarly journals Surface Texturing of Si with Periodically Arrayed Oblique Nanopillars to Achieve Antireflection

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 380
Author(s):  
Jun-Hyun Kim ◽  
Sanghyun You ◽  
Chang-Koo Kim
Keyword(s):  
Aspect Ratio ◽  
Plasma Etching ◽  
Surface Texturing ◽  
Light Reflection ◽  
Si Substrate ◽  
Weighted Mean ◽  
Optical Reflectance ◽  
Si Substrates ◽  
Aspect Ratios ◽  
Shadowing Effect

Si surfaces were texturized with periodically arrayed oblique nanopillars using slanted plasma etching, and their optical reflectance was measured. The weighted mean reflectance (Rw) of the nanopillar-arrayed Si substrate decreased monotonically with increasing angles of the nanopillars. This may have resulted from the increase in the aspect ratio of the trenches between the nanopillars at oblique angles due to the shadowing effect. When the aspect ratios of the trenches between the nanopillars at 0° (vertical) and 40° (oblique) were equal, the Rw of the Si substrates arrayed with nanopillars at 40° was lower than that at 0°. This study suggests that surface texturing of Si with oblique nanopillars reduces light reflection compared to using a conventional array of vertical nanopillars.

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.

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