In this article, we review special features of Gwyddion—a modular, multiplatform, open-source software for scanning probe microscopy data processing, which is available at http://gwyddion.net/. We describe its architecture with emphasis on modularity and easy integration of the provided algorithms into other software. Special functionalities, such as data processing from non-rectangular areas, grain and particle analysis, and metrology support are discussed as well. It is shown that on the basis of open-source software development, a fully functional software package can be created that covers the needs of a large part of the scanning probe microscopy user community.

https://www.degruyter.com/document/doi/10.2478/s11534-011-0096-2/pdf

Gwyddion: an open-source software for SPM data analysis

Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing

Manufacturing and measurement of freeform optics

The development of atomic force microscopy has evolved into a wide variety of microscopy and characterization techniques well beyond conventional imaging. The focus of this review is on characterization methods based on the scanning probe and their application in characterizing physical properties of soft materials. This consideration is broken into three major categories focusing on mechanical, thermal, and electrical/magnetic properties in addition to a brief review of high-resolution imaging. Surface spectroscopy is discussed to great extent and consideration includes procedural information, common pitfalls, capabilities, and their practical application in characterizing soft matter. Key examples of the method are presented to communicate the capabilities and impact that probe-based characterization techniques have had on the mechanical, thermal, and electrical characterization of soft materials.

Probing Soft Matter with the Atomic Force Microscopies: Imaging and Force Spectroscopy

Atomic and subnanometer resolution in ambient conditions by atomic force microscopy

With the nanopositioning and nanomeasuring machine (NPM-Machine) developed at the Technische Universitat Ilmenau, subnanometre resolution and nanometre uncertainty in a measuring volume of 25 × 25 × 5 mm3 have been demonstrated in the last few years. This machine allows the most various measuring problems to be solved. In practice, however, there are too many different requirements for sensing surfaces or for detecting structures. So, this paper deals with the development and also the improvement of several optical and tactile probes for application in the NPM-Machine. A focus probe with a spot size of approximately 0.5 µm, a working distance of 1.5 mm and a resolution of less than 1 nm was developed and adopted in the NPM-Machine. In the next step, the working distance was improved to exploit the full vertical range of the NPM-Machine of 5 mm. To realize tactile sensing, an atomic force probe and tactile stylus probe were developed on the basis of the focus probe. These probing systems can acquire measuring data only by scanning the surface sequentially and point-by-point. To increase data acquisition, we realized a sensor based on a white-light interference microscope and parallel sampling of 1600 × 1200 data points. First results of fringe evaluation with laser interferometer reference are presented.

http://iopscience.iop.org/article/10.1088/0957-0233/18/2/S27/pdf

New applications of the nanopositioning and nanomeasuring machine by using advanced tactile and non-tactile probes

Kelvin probe force microscopy (KPFM) is a method to detect the surface potential of micro- and nanostructured samples using a common atomic force microscope (AFM). The electrostatic force has a very long range compared to other surface forces. By using AFM systems under ambient conditions, KPFM measurements are performed using a non-contact regime at surface distances greater than 10 nm. This paper deals with a method to deconvolve the measured KPFM data with the objective to increase the lateral resolution. The KPFM signal is a convolution of an effective surface potential and a microscopic intrinsic point spread function, which allows the restoration of the measured data by linear deconvolution. In contrast to other papers [4], we have developed a new method to use the measured AFM tip shape as a basis to construct the point spread function. The linear shift-invariant channel is introduced as a signal formation model and a Wiener-supported deconvolution algorithm is applied to the measured data. The new method was demonstrated on a nanoscale test stripe pattern for lateral resolution and calibration of length scales (BAM-L200) manufactured by the Federal Institute for Materials Research and Testing, Germany. For the first time, a two-dimensional deconvolution of the KPFM data was able to be demonstrated. An increase in the lateral resolution compared to Strassburg et al (2005 Rev. Sci. Instrum. 76 083705) was accomplished. The results demonstrate the necessity of deconvolving the virtually topography-free probe data under ambient conditions.

https://iopscience.iop.org/article/10.1088/0957-0233/20/8/084017/pdf

Deconvolution of Kelvin probe force microscopy measurements—methodology and application

The electrical characterization of gallium nitride (GaN) nanocolumns with a length up to 1 μm and a diameter of about 30–80 nm grown on doped silicon is a challenge for nano analytics. To determine the conductivity of these nanocolumns, I – V characteristics were recorded by atomic force microscopy (AFM). To measure the conductivity of a single nanocolumn, a conductive AFM tip was placed at the top of the nanocolumn. The measured current/voltage characteristic of a single nanocolumn shows the typical performance of a Schottky contact, which is caused by the contact between the metallic AFM tip and the semiconductor material of the nanocolumn. The height of the Schottky barrier is dependent on the work function of the AFM tip metal used. The linear part of the curve was used to calculate the differential resistance, which was found to be about 13 Ω cm and slightly dependent on the diameter.

Electrical performance of gallium nitride nanocolumns

Abstract This article discusses methods to measure samples up to 25×25 mm2 using the NPMM [1] as an atomic force microscope (AFM) [2]. An entire scan at full resolution (10 nm) and 10 μm/s scan speed would take about 200 years. Therefore, overview scans with the AFM can be done to reduce the scan time, but these scans can induce aliasing artifacts due to sub-sampling. This paper gives a solution to that problem. The AFM camera is used for approximate orientation in the scan field. From an automatic optical area scan stitching software creates an overview image of about 2.6 GPixel with 0.5 μm resolution. The GEOtiff standard [3] is introduced to enable orientation in such big images. This format includes positioning information in the image and is used to solve the nano-orientation problem. This article further presents routines to create an overview image and a segmentation routine to detect structure domains. Since a combination of an AFM and optical scanning leads to higher positioning performance, both measurements are merged.

Navigation in a Large Measurement Volume by Using AFM Technology as a Sensor System in the NPMMNavigation in einem großen Messvolumen in der Nanopositionier- und Mess-Maschine (NPMM) mittels AFM-Technologie

This article presents white light interferometry as a new application for the nanopositioning and nanomeasuring machine
(NPMM). The NPMM was developed under the leadership of the Institute of Process Measurement and Sensor
Technology at the Technische Universitat Ilmenau (Germany) and allows highly exact dimensional and traceable
positioning with a resolution of 0.1 nm within a volume of 25 mm x 25 mm x 5 mm.
An application of white light interferometry was developed on the basis of these features which can utilize the device's
very high precision and large effective range, which enables the stitching of partitioned results without overlapping
measurements and expensive matching methods.
In order to extract height data from the interferograms, a robust, precise and fast method using matched filters in the
frequency domain has been put into practice. The filter templates are calculated according to a model function or are
directly sampled from the light source power spectrum, which has been previously analyzed once. Thus, light sources
with different spectral forms can be used.

T. Machleidt

Papers

New applications of the nanopositioning and nanomeasuring machine by using advanced tactile and non-tactile probes

Deconvolution of Kelvin probe force microscopy measurements—methodology and application

Electrical performance of gallium nitride nanocolumns

Navigation in a Large Measurement Volume by Using AFM Technology as a Sensor System in the NPMMNavigation in einem großen Messvolumen in der Nanopositionier- und Mess-Maschine (NPMM) mittels AFM-Technologie

White light interferometry in combination with a nanopositioning and nanomeasuring machine (NPMM)