„Eddy“ is an Atomic Force Microscopy
system for student's education. It bases on the approved Level AFM
setup and includes a full sample set and a large cantilever set.
Some special features:
CCD camera
forward and backward tracing
auto save and auto approach functions
distance spectroscopy
oscilloscope
voltage spectroscopy
Among the prepared experiments are the standard measurements as
contact mode
Students learn the principle of the laser deflection system and how to
adjust the system.They can take an image in contact mode and check the
difference between slow feedback speed (constant height mode) and fast
feedback speed (constant force mode).
With distance curves, they can calculate the sensitivity of the system
and calculate the contact force used in the experiments.
Dynamic mode
For the daily use of AFM, the imaging in dynamic mode is more common
than the contact mode, because tip and sample are spared.The
students learn the relation between force constant and resonance
frequency, repeat some knowledge about harmonic oscillating systems,
resonances and Q-factors and get introduced to the basics of lockin
amplification technique, which is used to evaluate the amplitudes and
phase shifts.In the acquired images, material contrast can be obtained in the phase
image in addition to the topography.
Lateral force mode
In contact mode, lateral forces are detectable and can be used to find
material contrast in inhomogeneous samples.
The experiment explains how LFM is working and the students learn to
understand, how to distinguish between topography-related signals and
material-related signals.
but also some more enhanced experiments like
Force Spectroscopy
Kelvin Probe Force Microscopy
Kelvin Probe Force Microscopy
Kelvin Probe Force Microscopy (KPFM) is a technique that allows to detect work function differences
on surfaces as well as local charges. It has undergone a long development and there are many different
kind of KPFM operation modes known. All KPFM mode have in common, that an alternating plus a dc bias is
applied between tip and sample. The forces resulting from the alternating voltage are used to generate a
feedback signal that controls the value of the dc bias. Usually, a signal of a lockin amplifier is compensated
to zero with the KPFM feedback.
Two of the available Anfatec SPM controllers offer KPFM capability: the AMU2.6 controller type
offers it for lockin frequencies up to 1 MHz and the AMU2.9-HighSpeed controller version offers
it for frequencies up to 10 MHz. In both cases, the lockin card includes four independent 2-phase
lockin amplifiers. They can be configured in a way, that AM-KPFM, Side band KPFM on the 2nd cantilever
resonance or FM-KPFM experiments can be performed.
AM-KPFM image of an Al / silicon surface taken with a DEP01 cantilever with Pt coating.
Topography (left) and Surface Potentoal (right). The Al wire is buried into the silicon surface and
shows the more positive surface potential. The silicon is covered with a thin oxide laser and the surface
potential slightly decays in dependence on the distance from the Al edge.
Resonance enhanced FM-KPFM image of an Al / silicon surface taken with a DEP01 cantilever with Pt coating.
Topography (left) and Surface Potentoal (right). In comparison to the AM-KPFM image, the potential contrast
is better localized due to the side band detection. There are also more potential features visible on the Al
surface. The potential difference between Al and Si is measured with 190 mV.
Magnetic Force Microscopy(2nd trace imaging)
Magnetic Force Microscopy
In Magnetic Force Microscopy (MFM), each line of the images is taken twice: the first trace is used to
get the topography information. The 2nd trace is following the topography in a certain height of several
nm and mainly detects long range interactions, such as interactions caused by magnetic forces. MFM employs
cantilevers with a magnetic coating, usually CrCo coated silicon tips.
Topography (left) and MFM Amplitude (right) images of a Bruker reference sample for MFM. Image Size: 1.5 �m x 1.5 �m.
Topography (left) and MFM Phase (right) images of a Bruker reference sample for MFM. Image size: 40 �m x 40 �m.
Electrical Force Microscopy
Electrical Force Microscopy
The field of electrical force detection in AFM is very wide. Here,
we have selected a technique, where the electrical forces are
separated from the topography with modulated voltage applied between
tip and sample.
The students can go through some basic formulas and finally measure on
a
provided transistor structure capacitance differences caused by
different thicknesses of oxide layers.
EFM Mode (Single trace)
Topography FWD
EFM Signal 1st Harmonic FWD
EFM Signal 2nd Harmonic FWD
EFM Mode (Dual trace = Lift Mode)
Topography FWD
2nd Trace Amplitude FWD
2nd Trace Phase FWD
All experiments are described step by step, that the student
can follow the instructions. The single instructions give a short introduction
in the theoretical knowledge and finish with a set of questions.
For more information click here:
Data Sheet
System parameters:
lateral resolution
better than 5 nm (at standard samples)
height resolution
better than 0,4 nm (atomic steps)
maximum scan range
30 m (standard, others possible on request)
maximum sample size
4 cm x 4 cm
manual positioning range
5 mm x 5 mm
accessories
130 cantilevers of different types, small empty
cantilever boxes, tweezers, sample holders, over 15 different samples
Microscope Description
The system consists of:
a base plate made from stone with wiring,
vibration isolation
microscope base:
3 integrated miniaturized stepper motors for head levelling
lateral coarse positioning with 6 mm travel range
self-adjustable grooves (head is always in same position)
calibrated scanner (about 30 m range)
electrical contact to sample (can be used for Electrical Force Microscopy)
standard AFM-head
laser diode maximum 3 mW, 670 nm with lens system
laser adjustment in three axis
integrated 4-quadrant photo-detector with amplifier electronics
adjustment of the laser beam onto the photo detector in two directions (X, Y)
built-in dither piezo for acoustical excitation in dynamic mode
integrated illumination
color-camera with microscope optic with a direct view onto the cantilever
uncomplicated mounting of the cantilever chips
high voltage amplifier V45C
DS4L-Modul with Interface to the AMU 2.4
control of the level station
8 x 24-bit D/A and 8 x 24-bit A/D channels
Anfatec Measurement Interface AMU 2.4 (PCI bus board with integrated LockIn amplifier)
tools: 1 calibration grating UMG01, 1 start-up set of cantilevers (15 pcs.), connection cables
English or German manual, certain tutorials for NC AFM, contact AFM, Scanner calibration
control computer:
64-bit AMD processor
17“ TFT monitor
video card
installed software: Windows XP, Anfatec Scan with GNU GPL, Anfatec Present
Accessories
Accessories
50 contact mode cantilever
50 dynamic mode cantilever
15 MFM cantilever
15 EFM cantilever
4 empty gel Pak for cantilevers
8 grating samples
6 EFM samples
1 LFM sample
2 MFM samples
30 empty sample holders
silver glue
2 tweezers
Optional Features
Optional features for Anfatec AFMs
(not
necessary for standard applications)
EFM Module for AM-KPFM and FM-KPFM
passive Vibration isolation table under the microscope
active Vibration isolation table under the microscope
separate tip contact for EFM
scanner linearisation
glass bell jar for acoustic protection
glass bell jar for vacuum application
additional cantilever packages and gratings
enhanced LFM mode sensitivity (spot like laser diode)
external lockin amplifier
SPIP – Danish software for image evaluation
Aluminum base plate for vacuum applications
Humidity sensor
EFM head with IR laser diode
Anfatec Present
Anfatec Present
- our software to evaluate your images -
filter functions (high pass, low pass,
Fourier, noise, mean,
..)
enhanced line and plane correction
data import and export
shows image information
histogram for brightness /contrast
colour palette variable
3D view
line and roughness analysis, FFT
copy function to other windows tools
unit cell correction (also for Omicron
pictures)
Besides its advantages for education, the Eddy Level AFM can
be used in the same laboratory for research purposes. There is no
limitation.
Software adjustments done for the students are totally free in
administration mode. The software is started with an option that points
to an initialization file. In this file, all pre-adjustments are stored.