RF-measurements
TE-OX provides the RF-measurements in a fraquancy range from 10 kHZ to 6,2 GHz .
AFM characterisations
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TE-OX proposes AFM measurements services on NX10 AFM from Park Systems that allow operating in following modes:
Our AFM is equipped with a heating stage to investigate temperature dependent materials properties (Temperature range: ambient to 180 °C)
The True Non-Contact mode preserves tip sharpness and sample surface, and you can get more accurate results. In the True Non-Contact mode, a piezoelectric modulator vibrates a cantilever at small amplitude and a fixed frequency near the resonant frequency of the cantilever. As the tip is brought closer to the sample, the van der Waals attractive force between tip and sample changes the amplitude and the phase of the cantilever’s vibration. These changes are monitored by the patented Z-servo feedback system of the Park AFMs, which maintains a tip-surface distance of just a few nanometers without damaging the sample surface or the tip end.
The contact mode is the simplest way to acquire the sample topography. The topography signal comes from the Z scanner position, which maintains the deflection of the cantilever constant on the sample surface.
In this alternative technique to non-contact mode, the cantilever again oscillates just above the surface, but at a much higher amplitude of oscillation. The bigger oscillation makes the deflection signal large enough for the control circuit, and hence an easier control for topography feedback. It produces modest AFM results but blunts the tip’s sharpness at a higher rate, ultimately speeding up the loss of its imaging resolution. |
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Electrical Modes
PinPoint™ nanoelectrical modes eliminate lateral shear forces between the cantilever tip and the surface, thus minimizing damage while ensuring high imaging quality and reproducibility for a wide range of samples over many consecutive measurements. PinPoint can be combined with other AFM modes to obtain information about electrical properties such as: • PinPoint Conductive AFM (C-AFM) • PinPoint Piezoresponse Force Microscopy (PFM) • PinPoint Scanning Spreading Resistance Microscopy (SSRM
Conductive AFM (C-AFM) in particular, simultaneously measures the topography and conductivity of a sample by scanning the surface with a conductive material coated tip as a nanoscale electrical probe at an applied DC bias.
Park AFMs feature the ability to conduct current voltage spectroscopy on specified point of the sample surface. The low noise of Park Systems’ conductive AFM options allows for the detection of extremely small changes in a sample’s electronic characteristics.
For EFM, the sample surface properties would be electrical properties and the interaction force will be the electrostatic force between the biased tip and sample. However, in addition to the electrostatic force, the van der Waals forces between the tip and the sample surface are always present. The magnitude of these van der Waals forces changes according to the tip-sample distance, and are therefore used to measure the surface topography. |
DC-EFM is capable of extremely high definition EFM results. Patented by Park Systems, DC-EFM actively applies an AC voltage bias to the cantilever and detects the amplitude and the phase change of the cantilever modulation with respect to the applied bias. DC-EFM provides the ability to monitor the second harmonic of the modulation which can be compared to the capacitance of a sample and enhances the electric force signal from the background intermolecular force.
Piezoresponse force microscopy (PFM) is a functional Atomic force microscopy (AFM) mode, which probes electromechanical material properties on the nanometer scale in addition to the sample topography. As a conductive tip scans the surface in contact, an AC voltage introduces an electromechanical response in piezoelectric compounds and thereby resolves local variations of piezoelectric and ferroelectric properties. PFM has gained increasing recognition for the unique information it can offer on the electromechanical coupling characteristics of various materials including actuators, sensors, and capacitors for modern communication technology.
Piezoresponse Force Spectroscopy mode measures the local amplitude/phase response to a DC bias between tip and sample surface. The polarity of local piezoelectric domain switches depend on the sign and amount of applied voltage.
Kelvin Probe Force Microscopy (KPFM) or surface potential microscopy is one of the AFM variations, which enables measurement of Contact Potential Difference (CPD) between a reference surface (tip) and surface to analyse. When the tip approaches the surface at a distance d, an electric force is generated between the sample and the tip, due to the difference of the Fermi level. While the electrical contact occurs, the Fermi levels will align through electron current flow. However, the vacuum levels are not aligned anymore and VCPD is formed between the sample and tip. An electrical force acts on the contact area can be nullified by application of the external potential VDC equal to VCPD with opposite direction. |
Nanomechanical Modes
- NANOINDENTATION
Atomic force microscopy (AFM)-based Nanoindentation quantitatively characterizes local mechanical properties of target specimen. In this technique, a hard AFM indentation tip with known mechanical properties presses against a sample surface until the tip deforms the surface.