Phase imaging quality improvement by modification of AFM probes’ cantilever

Abstract

Imaging of the surface of materials by atomic force microscopy under tapping and phase imaging mode, with use of modified probes is addressed. In this study, the circularly shaped holes located in varying distance from the probe base, were cut out by focused ion beam. Such modification was a consequence of the results of the previous experiments (probe tip sharpening and cantilever thinning) where significant improvement of image quality in tapping and phase imaging mode has been revealed. The solution proposed herein gives similar results, but is much simpler from the technological point of view. Shorter exposition time of the tip onto gallium ions during FIB processing allows to reduce material degradation. The aim of this modification was to change harmonic oscillators' properties in the simplest and fastest way, to obtain stronger signal for higher resonant frequencies, which can be advantageous for improving the quality of imaging in PI mode. Probes shaped in that way were used for AFM investigations with Bruker AFM nanoscope 8. As a testing material, titanium roughness standard sample, supplied by Bruker, was used. The results have shown that the modifications performed within these studies influence the oscillation of the probes, which in some cases may result in deterioration of the imaging quality under tapping mode for one or both self-resonant frequencies. However, phase imaging results obtained using modified probes are of higher quality. The numerical simulations performed by application of finite element method were used to explain the results obtained experimentally. Phenomenon described within this study allows to apply developed modelling methodology for prediction of effects of various modifications on the probes' tip, and as a result, to predict how proposed modifications will affect AFM imaging quality.

General Resolution Enhancement Method in Atomic Force Microscopy Using Deep Learning

“…Generally speaking, low‐resolution images certainly contain insufficient information, which may cause some of the important features, including grain boundary, surface defect, dislocation and interface unclear or even ignored. Hence, several methods and techniques were proposed to enhance the resolution and quality of the AFM images, such as by improving the shape and properties of the tip or cantilever, the development and application of the multiple frequency excitation techniques, the contour metrology, and the combination with other microscopy techniques . Generally speaking, achieving higher‐resolution image is a long‐term goal in all types of microscopic techniques.…”

“…Hence, several methods and techniques were proposed to enhance the resolution and quality of the AFM images, such as by improving the shape and properties of the tip or cantilever, [11][12][13][14] the development and application of the multiple frequency excitation techniques, [15][16][17] the contour metrology [18] and the combination with other microscopy techniques. [19] Generallyspeaking, to achieve higher resolution image is a long-term goal in all types of microscopic techniques.…”

“…In this study, a very deep convolution neural network is developed to derive a high-resolution topography image from a low-resolution topography image. Hence, several methods and techniques were proposed to enhance the resolution and quality of the AFM images, such as by improving the shape and properties of the tip or cantilever, [11][12][13][14] the development and application of the multiple frequency excitation techniques, [15][16][17][18] the contour metrology, [19] The derived high-resolution AFM images are comparable with the experimental measured high-resolution images measured at the same locations.…”

“…[3][4][5] However, the unavoidable experimental errors, such as "tip crash," [6] the cross-talk between topographic and electrostatic information, [7] the large height variation of the sample surface, [8] and the influence by the properties of the sample or the ambient environment [9] can severely reduce the spatial resolution of the AFM images. Hence, several methods and techniques were proposed to enhance the resolution and quality of the AFM images, such as by improving the shape and properties of the tip or cantilever, [11][12][13][14] the development and application of the multiple frequency excitation techniques, [15][16][17][18] the contour metrology, [19] [10] Generally speaking, low-resolution images certainly contain insufficient information, which may cause some of the important features, including grain boundary, surface defect, dislocation and interface unclear or even ignored.…”

Imaging Quality and Fatigue Quantification of Ocular Optical System

“…Performance of an ordinary optical system is generally assessed by imaging quality [22]- [24]. Poor imaging tends to present low resolution with distortion.…”