Analyzing Atomic Force Micrographs Using Spectral Methods

1995 ◽  
Vol 386 ◽  
Author(s):  
Sameer D. Halepete ◽  
H. C. Lin ◽  
Simon J. Fang ◽  
C. R. Helms
Keyword(s):  
Silicon Surface ◽  
Critical Parameter ◽  
Spectral Information ◽  
Root Mean Square Roughness ◽  
Atomic Force ◽  
Frequency Components ◽  
Height Data ◽  
Insight Into ◽  
Atomic Force Micrographs ◽  
Analyze Data

ABSTRACTMicroroughness is a critical parameter in ULSI device interface reliability and has been shown to effect several critical MOS electrical properties. The atomic force microscope (AFM) has become the instrument of choice for silicon surface microroughness analysis. The parameters usually specified to characterize roughness are average and root mean square roughness. However, these parameters are spatial averages and can have the same value for two significantly different surfaces. Spectral analysis using the Fast Fourier Transform (FFT) has been applied as a powerful tool to analyze AFM data by looking at roughness as a function of spatial wavelength. The Fast Hartley Transform, being a real transform, is faster than the FFT and is better suited for this analysis. It has been used here to derive spectral information from the AFM height data. Before evaluating the transform, cancellation of any tilt or warp in the AFM data is done to remove frequency components which interfere with other spectral information. A PC-based computer program to determine the transform and its magnitude will be described. The application of this method to analyze data from Si and SiO2 surfaces as a function of pre-oxidation cleaning chemistry will be presented. Significantly better insight into the spatial distribution of roughness is obtained, when compared to previous implementations.

The Reactive Formation of Diblock Copolymer at a Polymer/Polymer Interface and its Effect on Interfacial Structure

2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko
Keyword(s):  
Molecular Weight ◽  
Interfacial Structure ◽  
Root Mean Square Roughness ◽  
Radius Of Gyration ◽  
Interfacial Region ◽  
Force Microscopy ◽  
Amino Terminal ◽  
Polymer Interface ◽  
Atomic Force ◽  
Time Required

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.

Optical Properties of Sputtered Silver Granular Films

2005 ◽  
Vol 480-481 ◽  
pp. 287-292 ◽  
Author(s):  
S.E. Paje ◽  
F. Teran ◽  
J.M. Riveiro ◽  
J. Llopis ◽  
M.A. García ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Optical Absorption ◽  
Surface Morphology ◽  
Silver Clusters ◽  
Plasmon Excitation ◽  
Granular Films ◽  
Silver Films ◽  
Atomic Force ◽  
Atomic Force Micrographs

In this research we study optical absorption and morphology of silver films prepared with a sputtering method. Silver granular films are obtained on a glass substrate for films with thickness smaller than about 60 Å. Superficial silver clusters of around 100 nm in diameter are clearly seen in the atomic force micrographs. The absorption of these samples are characterized by plasmon excitation in the 450-650 nm spectral range, which differs from the known excitation of silver nanoparticles fabricated by different techniques. The optical absorption of silver granular films depend on sputtering conditions like substrate temperature or deposition rate and correlates with the surface morphology.

A Fresh Insight Into the Microcantilever-Sample Interaction Problem in Non-Contact Atomic Force Microscopy

2004 ◽  
Vol 126 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Nader Jalili ◽  
Mohsen Dadfarnia ◽  
Darren M. Dawson
Keyword(s):  
Imaging Techniques ◽  
Interaction Force ◽  
Intermolecular Forces ◽  
Scanning Tunneling ◽  
Atomic Interaction ◽  
Force Estimation ◽  
Contact Mode ◽  
Distributed Parameters ◽  
Atomic Force ◽  
Insight Into

The atomic force microscope (AFM) system has evolved into a useful tool for direct measurements of intermolecular forces with atomic-resolution characterization that can be employed in a broad spectrum of applications. The non-contact AFM offers unique advantages over other contemporary scanning probe techniques such as contact AFM and scanning tunneling microscopy, especially when utilized for reliable measurements of soft samples (e.g., biological species). Current AFM imaging techniques are often based on a lumped-parameters model and ordinary differential equation (ODE) representation of the micro-cantilevers coupled with an adhoc method for atomic interaction force estimation (especially in non-contact mode). Since the magnitude of the interaction force lies within the range of nano-Newtons to pica-Newtons, precise estimation of the atomic force is crucial for accurate topographical imaging. In contrast to the previously utilized lumped modeling methods, this paper aims at improving current AFM measurement technique through developing a general distributed-parameters base modeling approach that reveals greater insight into the fundamental characteristics of the microcantilever-sample interaction. For this, the governing equations of motion are derived in the global coordinates via the Hamilton’s Extended Principle. An interaction force identification scheme is then designed based on the original infinite dimensional distributed-parameters system which, in turn, reveals the unmeasurable distance between AFM tip and sample surface. Numerical simulations are provided to support these claims.

Slip Length Measurement of Water Flow on Graphite Surface Using Atomic Force Microscope

2014 ◽  
Vol 941-944 ◽  
pp. 1581-1584 ◽  
Author(s):  
Da Yong Li ◽  
Da Lei Jing ◽  
Yun Lu Pan ◽  
Khurshid Ahmad ◽  
Xue Zeng Zhao
Keyword(s):  
Atomic Force Microscope ◽  
Water Flow ◽  
Drag Force ◽  
Silicon Surface ◽  
Slip Length ◽  
Graphite Surface ◽  
Length Measurement ◽  
Hydrodynamic Drag ◽  
Experimental Measurements ◽  
Atomic Force

In this paper, we present experimental measurements of slip length of deionized (DI) water flow on a silicon surface and a graphite surface by using atomic force microscope. The results show that the measured hydrodynamic drag force is higher on silicon surface than that on graphite surface, and a measured slip length about 10 nm is obtained on the later surface.

scholarly journals Dental calculus: Nano-characterization

2012 ◽  
Vol 59 (3) ◽  
pp. 154-159
Author(s):  
Djurica Grga ◽  
Marina Marjanovic ◽  
Igor Hut ◽  
Bojan Dzeletovic ◽  
Djuro Koruga
Keyword(s):  
Magnetic Field Gradient ◽  
Dental Calculus ◽  
Oral Diseases ◽  
Force Microscopy ◽  
Atomic Force ◽  
Light Matter Interaction ◽  
The Magnetic Field ◽  
Very High ◽  
Insight Into

Emerging technologies and new nanoscale information have potential to transform dental practice by improving all aspects of diagnostics and therapy. Nanocharacterization allows understanding of oral diseases at molecular and cellular levels which eventually can increase the success of prevention and treatment. Opto-magnetic spectroscopy (OMS) is a promising new technique based on light-matter interaction which allows insight into the quantum state of matter. Since biomolecules and tissues are usually paramagnetic or diamagnetic materials it is possible to determine the dynamics of para-and diamagnetism at different teeth structures using that method. The topography of the surface of a sample can be obtained with a very high resolution using atomic force microscopy (AFM), which allows observation of minimal changes up to 10 nm, while magnetic force microscopy (MFM) is used to record the magnetic field gradient and its distribution over the surface of a sample. The aim of this study was to determine the possibility of AFM and MFM for the characterization of dental calculus, and a potential application of OMS for the detection of subgingival dental calculus.

Ion energy dependence of film properties for diamond-like carbon prepared with plasma-assisted deposition

2001 ◽  
Vol 16 (11) ◽  
pp. 3034-3037 ◽  
Author(s):  
Cao Zexian
Keyword(s):  
Carbon Films ◽  
Root Mean Square Roughness ◽  
Film Properties ◽  
Ion Energy ◽  
Atomic Force ◽  
Wave Resonance ◽  
Electron Cyclotron Wave ◽  
20 Nm ◽  
Maximum Content ◽  
Resonance Plasma

Hydrogen-free diamondlike carbon films were prepared on Si(100) with electron cyclotron wave-resonance plasma, which serves to sputter the graphite target and to simultaneously bombard the growing surface. Direct penetration of postionized carbon atoms (up to 140 eV) in addition to the momentum transfer from Ar plasma facilities the formation of the Ta–C structure. Surface morphology, mechanical, and optical properties of the deposits were examined with respect to the ion energy. Atomic force microscope images revealed island morphology in deposits with a typical root-mean-square roughness of 20 nm. A maximum content of about 70% for the fourfold-bonded structure was estimated from the Raman profiles, giving rise to a micro hardness of 60 ± 5 GPa.

Surface Instability and Associated Roughness of Pendeo-epitaxy GaN (0001) Films Grown via Metalorganic Vapor Phase Epitaxy

2001 ◽  
Vol 693 ◽  
Author(s):  
Amy M. Roskowski ◽  
Peter Q. Miraglia ◽  
Edward A. Preble ◽  
Sven Einfeldt ◽  
Robert F. Davis
Keyword(s):  
Smooth Surface ◽  
Growth Process ◽  
Root Mean Square Roughness ◽  
Optimum Temperature ◽  
Force Microscopy ◽  
Atomic Force ◽  
Process Route ◽  
Vertical Growth Rate ◽  
Hillock Growth ◽  
Sidewall Surface

AbstractA growth process route that results in thin film GaN templates with a smooth surface morphology at the optimum temperature of 1020°C has been developed. Atomic force microscopy (AFM) reveals hillocks on films grown above 1020°C. Hillocks resulted from the rotation of heterogeneous steps formed at pure screw or mixed dislocations which terminated on the (0001) surface. Growth of the latter feature was controlled kinetically by temperature through adatom diffusion. The 106 cm-2 density of the hillocks was reduced through growth on thick GaN templates and regions of pendeo-epitaxy (PE) overgrowth with lower pure screw or mixed dislocations. Smooth PE surfaces were obtained at temperatures that reduced the lateral to vertical growth rate but also retarded hillock growth that originated in the stripe regions. The (1120 ) PE sidewall surface was atomically smooth, with a root mean square roughness value of 0.17 nm which was the noise limited resolution of the AFM measurements.

scholarly journals A review of demodulation techniques for multifrequency atomic force microscopy

2020 ◽  
Vol 11 ◽  
pp. 76-91 ◽  
Author(s):  
David M Harcombe ◽  
Michael G Ruppert ◽  
Andrew J Fleming
Keyword(s):  
Atomic Force Microscopy ◽  
Sampling Rate ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Direct Design ◽  
Field Programmable ◽  
Frequency Components ◽  
Atomic Force Microscopy Imaging ◽  
Lock In

This article compares the performance of traditional and recently proposed demodulators for multifrequency atomic force microscopy. The compared methods include the lock-in amplifier, coherent demodulator, Kalman filter, Lyapunov filter, and direct-design demodulator. Each method is implemented on a field-programmable gate array (FPGA) with a sampling rate of 1.5 MHz. The metrics for comparison include the sensitivity to other frequency components and the magnitude of demodulation artifacts for a range of demodulator bandwidths. Performance differences are demonstrated through higher harmonic atomic force microscopy imaging.

scholarly journals Fully soluble self-doped poly(3,4-ethylenedioxythiophene) with an electrical conductivity greater than 1000 S cm−1

2019 ◽  
Vol 5 (4) ◽  
pp. eaav9492 ◽  
Author(s):  
Hirokazu Yano ◽  
Kazuki Kudo ◽  
Kazumasa Marumo ◽  
Hidenori Okuzaki
Keyword(s):  
Electrical Conductivity ◽  
Critical Parameter ◽  
Colloidal Particles ◽  
Average Distance ◽  
Charge Carriers ◽  
High Electrical Conductivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Technical Issues

Wet-processable and highly conductive polymers are promising candidates for key materials in organic electronics. Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is commercially available as a water dispersion of colloidal particles but has some technical issues with PSS. Here, we developed a novel fully soluble self-doped PEDOT (S-PEDOT) with an electrical conductivity as high as 1089 S cm−1without additives (solvent effect). Our results indicate that the molecular weight of S-PEDOT is the critical parameter for increasing the number of nanocrystals, corresponding to the S-PEDOT crystallites evaluated by x-ray diffraction and conductive atomic force microscopic analyses as having high electrical conductivity, which reduced both the average distance between adjacent nanocrystals and the activation energy for the hopping of charge carriers, leading to the highest bulk conductivity.

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