Size Reduction of Silicon Nanopillars by Photo-Electrochemical Etching

2000 ◽  
Vol 638 ◽  
Author(s):  
Robert Juhasz ◽  
Jan Linnros ◽  
Pascal Kleimann
Keyword(s):  
Electron Beam Lithography ◽  
Pore Formation ◽  
Etch Rate ◽  
Electrochemical Etching ◽  
Local Scale ◽  
Size Reduction ◽  
Negative Bias ◽  
Applied Bias ◽  
High Bias ◽  
Scanning Electron

AbstractSilicon nanopillars, formed by electron beam lithography, were electrochemically etched to provide controlled size reduction. The smallest dimensions achieved were pillars of 15 nm in diameter, restricted mainly by the scanning electron microscope used for characterization. The etch rate was mainly determined by the photogeneration of carriers, by the HF concentration and by the applied voltage bias. The applied bias also controlled the resulting shape of the pillars such that a high bias resulted in etching of the pillar top whereas a negative bias caused etching only at the pillar base. For 0 V, a relatively conform etching of the pillar was observed. We discuss these phenomena in terms of electropolishing or pore formation effects on a local scale.

scholarly journals Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 286
Author(s):  
Ashfaq Ali ◽  
Naveed Ullah ◽  
Asim Ahmad Riaz ◽  
Muhammad Zeeshan Zahir ◽  
Zuhaib Ali Khan ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Mechanical Stability ◽  
Electrochemical Etching ◽  
Research Work ◽  
Cone Angle ◽  
Quartz Tuning Fork ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
High Quality ◽  
Scanning Electron

Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM).

Reactive Ion Etching of GaSb, (Ai,Ga)Sb, and InAs for Novel Device Applications.

1990 ◽  
Vol 216 ◽  
Author(s):  
D.C. La Tulipe ◽  
D.J. Frank ◽  
H. Munekata
Keyword(s):  
Etch Rate ◽  
Reactive Ion Etching ◽  
Scanning Electron Micrographs ◽  
Electrical Characteristics ◽  
Ion Etching ◽  
Novel Device ◽  
Physical Sputtering ◽  
Chlorine Gas ◽  
Device Applications ◽  
Scanning Electron

ABSTRACT-Although a variety of novel device proposals for GaSb/(Al,Ga)Sb/InAs heterostructures have been made, relatively little is known about processing these materials. We have studied the reactive ion etching characteristics of GaSb, (AI,Ga)Sb, and InAs in both methane/ hydrogen and chlorine gas chemistries. At conditions similar to those reported elsewhere for RIE of InP and GaAs in CH4/H2, the etch rate of (AI,Ga)Sb was found to be near zero, while GaSb and InAs etched at 200Å/minute. Under conditions where the etch mechanism is primarily physical sputtering, the three compounds etch at similar rates. Etching in Cl2 was found to yield anisotropic profiles, with the etch rate of (AI,Ga)Sb increasing with Al mole fraction, while InAs remains unetched. Damage to an InAs “stop layer” was investigated by sheet resistance and mobility measurements. These etching techniques were used to fabricate a novel InAs-channel FET composed of these materials. Several scanning electron micrographs of etching results are shown along with preliminary electrical characteristics.

NEGATIVE BIAS TEMPERATURE INSTABILITY IN TIN/HF-SILICATE BASED GATE STACKS

2007 ◽  
Vol 17 (01) ◽  
pp. 129-141
Author(s):  
N. A. CHOWDHURY ◽  
D. MISRA ◽  
N. RAHIM
Keyword(s):  
Interface State ◽  
Initial Time ◽  
Negative Bias ◽  
Gate Stacks ◽  
Negative Bias Temperature Instability ◽  
Threshold Voltage Shift ◽  
Temperature Instability ◽  
Bias Temperature Instability ◽  
High Bias ◽  
The Impact

This work studies the effects of negative bias temperature instability (NBTI) on p-channel MOSFETS with TiN/HfSi x O y (20% SiO 2 based high-κ gate stacks under different gate bias and elevated temperature conditions. For low bias conditions, threshold voltage shift (ΔVT) is most probably due to the mixed degradation within the bulk high-κ. For moderately high bias conditions, H-species dissociation in the presence of holes and subsequent diffusion may be initially responsible for interface state and positively charged bulk trap generation. Initial time, temperature and oxide electric field dependence of ΔVT in our devices shows an excellent match with that of SiO 2 based devices, which is explained by reaction-diffusion (R-D) model of NBTI. Under high bias condition at elevated temperatures, due to higher Si - H bond-annealing/bond-breaking ratio, the experimentally observed absence of the impact ionization induced hot holes at the interfacial layer (IL)/ Si interface probably limits the interface state generation and ΔVT as they quickly reach saturation.

In Situ Observation of an Electrochemical Etching Reaction in Silicon

1995 ◽  
Vol 404 ◽  
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Pore Formation ◽  
Electrochemical Etching ◽  
Ex Situ ◽  
In Situ Observation ◽  
Specimen Holder

AbstractWe describe a TEM specimen holder which has been designed and constructed in order to observe the process of electrochemical pore formation in silicon. The holder incorporates electrical feedthroughs and a sealed reservoir for the electrolyte and it accepts lithographically patterned silicon specimens. We present ex situ observations of progressive pore propagation and show dynamic, in situ observations of electrolyte movement within the pores.

On the Relationship between Inclusions and Pores, Part II: Dendritic Structure, Pressure Drop in the Liquid and Pore Precipitation

2014 ◽  
Vol 790-791 ◽  
pp. 302-307 ◽  
Author(s):  
Arash Safavi Nick ◽  
Hasse Fredriksson
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Pore Formation ◽  
Pressure Field ◽  
Primary Dendrite ◽  
Dendritic Structure ◽  
Steel Sample ◽  
Continuously Cast ◽  
The Relationship ◽  
Scanning Electron

There is a relationship between pores and inclusions. As hypothesis goes, inclusions have an affinity to gather inside the pores and form clusters. Focus of this paper is how solidified dendritic structure affects the pressure field in the liquid and pore precipitation in austenitic stainless steel. Steel sample is a continuously cast bloom. Temperature profile and width of the mushy zone of the strand is modeled according to a constant temperature at the strands surface. Thermal analysis has been performed with differential thermal analysis (DTA) and differential scanning calorimeter (DSC). Dendrite arm spacing (DAS) is measured with light optical microscopy (LOM) and scanning electron microscopy (SEM). DAS is represented as the weight average of the distance between parallel sets of primary dendrite stems. Pressure field is calculated based on Darcys law. Pore formation is described through segregation of the gas components and pressure field in the liquid.

Measurement of Arrays of Dots Produced by Electron-beam Lithography

2006 ◽  
Vol 961 ◽  
Author(s):  
Philip C. Hoyle ◽  
Ian Laidler
Keyword(s):  
Electron Beam ◽  
Standard Deviation ◽  
Electron Beam Lithography ◽  
Tool Development ◽  
Patterned Media ◽  
Tool Performance ◽  
Scanning Electron

ABSTRACTElectron-beam mastering of templates for patterned media presents a challenge to the toolmaker to simultaneously meet throughput, resolution and placement requirements. Fundamental to tool development is the ability to measure the placement to true grid of shapes as small as 7 nm over the whole substrate. In this article we describe a technique, consisting of acquiring and analyzing scanning electron (SE) micrographs, for measuring the placement errors in lithography similar to that required for patterned media, albeit over a few square microns and without scale and orthogonality components. The method enabled the measurement of placement errors of dots in an array with accuracy down to about 2 nm. The technique was used to benchmark current X-Y tool performance and the smallest 3× standard deviation of placement error was found to be around 4.5 nm. A clearer understanding of the necessary tool improvements was obtained. The use of the technique as basis for measuring errors to true grid over the entire substrate is discussed.

Spot Electron-Beam Lithography as a Novel Method of High Resolution Pattern Nanofabrication

2014 ◽  
Vol 215 ◽  
pp. 459-461
Author(s):  
Alexander S. Samardak ◽  
Margarita V. Anisimova ◽  
Alexey V. Ognev ◽  
Vadim Yu. Samardak ◽  
Liudmila A. Chebotkevich
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Electron Beam Lithography ◽  
The Novel ◽  
Practical Applications ◽  
Novel Method ◽  
20 Nm ◽  
Scanning Electron

We present a novel method of pattern nanofabrication with high resolution and small shape defects using the traditional electron-beam lithography (EBL) or only a scanning electron microscope (SEM). Our method of Spot EBL is extremely fast, highly scalable on big areas, capable of sub-20 nm resolution and fabrication of polymer patterns with complicated shapes. We show the nanostructure images fabricated by Spot EBL and propose practical applications of the novel method.

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