Development of a traceable cantilever calibration device. - In: SMSI 2021, (2021), S. 57-58
https://doi.org/10.5162/SMSI2021/A3.3
Adjustment concept for compensating stiffness and tilt sensitivity of a novel monolithic EMFC weighing cell. - In: SMSI 2021, (2021), S. 53-54
This paper describes the experimental investigation of a new adjustment concept for planar monolithic high precision electromagnetic force compensated weighing cells. The concept allows to adjust the stiffness and the tilt sensitivity of the compliant mechanisms to an optimum. A new prototype mechanism is set up and adjusted according to the developed mechanical model. For evaluation of the concept, the system was tested on a high precision tilt table and under high vacuum conditions.
https://doi.org/10.5162/SMSI2021/A3.1
New opportunities for measurement and sensor technology through digitization. - In: SMSI 2021, (2021), S. 25-26
https://doi.org/10.5162/SMSI2021/PT1
Foreword to the special issue on "Tip- and laser-based 3D nanofabrication in extended macroscopic working areas". - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 131
https://doi.org/10.1007/s41871-021-00113-7
In-situ evaluation of the pitch of a reflective-type scale grating by using a mode-locked femtosecond laser. - In: Applied Sciences, ISSN 2076-3417, Bd. 11 (2021), 17, 8028, S. 1-16
Major modifications are made to the setup and signal processing of the method of in-situ measurement of the pitch of a diffraction grating based on the angles of diffraction of the diffracted optical frequency comb laser emanated from the grating. In the method, the improvement of the uncertainty of in-situ pitch measurement can be expected since every mode in the diffracted optical frequency comb laser can be utilized. Instead of employing a Fabry-Pérot etalon for the separation of the neighboring modes in the group of the diffracted laser beams, the weight-of-mass method is introduced in the method to detect the light wavelength in the Littrow configuration. An attempt is also made to reduce the influence of the non-uniform spectrum of the optical comb laser employed in the setup through normalization operation. In addition, an optical alignment technique with the employment of a retroreflector is introduced for the precise alignment of optical components in the setup. Furthermore, a mathematical model of the pitch measurement by the proposed method is established, and theoretical analysis on the uncertainty of pitch measurement is carried out based on the guide to the expression of uncertainty in measurement (GUM).
https://doi.org/10.3390/app11178028
Carrier mobility in semiconductors at very low temperatures. - In: Engineering proceedings, ISSN 2673-4591, Bd. 6 (2021), 1, 86, insges. 5 S.
Carrier mobilities and concentrations were measured for different p- and n-type silicon materials in the temperature range 0.3-300 K. Simulations show that experimentally determined carrier mobilities are best described in this temperature range by Klaassen's model. Freeze-out reduces the carrier concentration with decreasing temperature. Freeze-out, however, depends on the dopant type and initial concentration. Semi-classical calculations are useful only for temperatures above 100 K. Otherwise quantum mechanical calculations are required.
https://doi.org/10.3390/I3S2021Dresden-10086
Processing and analysis of long-range scans with an atomic force microscope (AFM) in combination with nanopositioning and nanomeasuring technology for defect detection and quality control. - In: Sensors, ISSN 1424-8220, Bd. 21 (2021), 17, 5862, insges. 17 S.
This paper deals with a planar nanopositioning and -measuring machine, the so-called nanofabrication machine (NFM-100), in combination with a mounted atomic force microscope (AFM). This planar machine has a circular moving range of 100 mm. Due to the possibility of detecting structures in the nanometre range with an atomic force microscope and the large range of motion of the NFM-100, structures can be analysed with high resolution and precision over large areas by combining the two systems, which was not possible before. On the basis of a grating sample, line scans over lengths in the millimetre range are demonstrated on the one hand; on the other hand, the accuracy as well as various evaluation methods are discussed and analysed.
https://doi.org/10.3390/s21175862
Compensating aberration induced error in differential confocal microscopy. - In: Optical Measurement Systems for Industrial Inspection XII, (2021), S. 117820P-1-117820P-10
Confocal microscopy is a working horse of optical profilometry since decades. It is a pointwise measurement method, where the whole sample must be scanned in all three dimensions. The high lateral resolution thereby outstrips its lowered scanning speed compared to widefield based principles. Furthermore, for a single 3D surface, even single-digit nanometre depth-resolution has been shown. However, albeit such high axial resolution, the accuracy may suffer from sample or optics induced wavefront distortions that differ from point to point. The acquired signal then experiences a shift that leads to a wrong acquired depth. Here we model this error through a low NA scalar model. We further present a method to compensate this error significantly by enhancing the principle of differential confocal microscopy. Theoretical results show the possibility for ideal compensation of the error caused by such in-stationary aberrations in confocal depth measurements.
https://doi.org/10.1117/12.2592392
Metrological investigation of a scanning electrostatic force microscope on a nano-positioning and nano-measuring machine. - In: Measurement science and technology, ISSN 1361-6501, Bd. 32 (2021), 10, 104012, insges. 7 S.
A surface profile measurement system was developed by combining a scanning electrostatic force microscope (SEFM) and a nano-measuring machine (NMM-1) and its characteristics were evaluated. SEFM is a type of scanning probe microscope (SPM) advocated in 2012. In SEFM, eliminating the trade-off between measurement accuracy, measurement speed, and stability has been a problem. As with other SPMs, the positioning accuracy of the probe and sample directly affects the measurement accuracy in SEFM. In this research, the SEFM principle was applied to the NMM-1, which is a high-precision positioning platform that achieves an uncertainty of smaller than 10 nm. In order to improve the force detection sensitivity, a probe polishing and assembling procedures was devised and, as a result, the quality factor of the sensor has been significantly improved. Furthermore, a method for optimizing scan parameters based on a theoretical model was proposed. The noise level of the measurement results was reduced by setting appropriate parameters, which agreed well with the theory. Profile measurements utilizing the developed measurement system were performed on line-and-space samples with an amplitude of 270 nm and a pitch of 10 [my]m. The results were compared with a conventional atomic force microscope as a reference. A surface measurement was performed on the sample, and a complete non-contact scan of a measurement range of 25 [my]m × 25 [my]m was demonstrated.
https://doi.org/10.1088/1361-6501/abf30c
Tip- and laser-based 3D nanofabrication in extended macroscopic working areas. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 132-148
The field of optical lithography is subject to intense research and has gained enormous improvement. However, the effort necessary for creating structures at the size of 20 nm and below is considerable using conventional technologies. This effort and the resulting financial requirements can only be tackled by few global companies and thus a paradigm change for the semiconductor industry is conceivable: custom design and solutions for specific applications will dominate future development (Fritze in: Panning EM, Liddle JA (eds) Novel patterning technologies. International society for optics and photonics. SPIE, Bellingham, 2021. https://doi.org/10.1117/12.2593229). For this reason, new aspects arise for future lithography, which is why enormous effort has been directed to the development of alternative fabrication technologies. Yet, the technologies emerging from this process, which are promising for coping with the current resolution and accuracy challenges, are only demonstrated as a proof-of-concept on a lab scale of several square micrometers. Such scale is not adequate for the requirements of modern lithography; therefore, there is the need for new and alternative cross-scale solutions to further advance the possibilities of unconventional nanotechnologies. Similar challenges arise because of the technical progress in various other fields, realizing new and unique functionalities based on nanoscale effects, e.g., in nanophotonics, quantum computing, energy harvesting, and life sciences. Experimental platforms for basic research in the field of scale-spanning nanomeasuring and nanofabrication are necessary for these tasks, which are available at the Technische Universität Ilmenau in the form of nanopositioning and nanomeasuring (NPM) machines. With this equipment, the limits of technical structurability are explored for high-performance tip-based and laser-based processes for enabling real 3D nanofabrication with the highest precision in an adequate working range of several thousand cubic millimeters.
https://doi.org/10.1007/s41871-021-00110-w