Department of Physics, Chungbuk National University
Atomic force microscopy (AFM) has been actively developed from a surface imaging tool into a quantitative analysis tool for materials at the nanoscale. The use of AFM to the material analysis shows that the macroscopic probe tip not only senses but also quantitatively measures the atomic interaction between the tip and the sample. This capability of AFM has opened a wide range of novel opportunities in nanoscience and technology. In this talk, I will present atomic force microscopy and spectroscopy, and several applications to quantitative interaction measurements. In particular, I will introduce a new type of rheometer based on AFM, capable of rheology of a single micron-sized sessile drop of soft matter, for the clinical application of human infertility. The AFM is now not only an imaging tool for solids but also a quantitative analysis tool for liquids.
Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Korea
Plasmonic nano-cavities can enhance and control a range of light-matter interactions at the nanoscale. This manipulation of optical properties through plasmon coupling is allowed even at room temperature with extremely small mode volume. Yet, in most studies, static geometries are used which put constraints on the ability to control coupling strength and induce coupling to different emitters with the same cavity. To achieve the desired dynamic nano-cavity, I present plasmonic tip-cavity which enables reversible control of light-matter interactions from weak to strong coupling regime. The tip-cavity is formed between a plasmonic tip and a metal substrate and the cavity gap is dynamically controlled by atomic force feedback between them. In this talk, I will demonstrate a range of light-matter interactions in low-dimensional quantum materials, which are probed and controlled by plasmonic tip-cavity.
Figure 1. Illustration of tip-enhanced nano-spectroscopy and -imaging to probe and control quantum light-mater interactions in van der Waals materials.
Department of Physics, Research Institute of Physics and Chemistry,
Jeonbuk National University, Jeonju 54896, Korea
Quartz tuning fork (QTF) has a capability of atomic force sensor in the field of scanning probe microscopy (SPM) with a high stiffness as a sensitive and stable force sensor. The high stiffness (intrinsic property) of the QTF sensor overcomes the tip instability near the surface called “jump-to-contact issue” due to attractive force and formation of the nanoscale water meniscus between the tip and the surface when the tip approaches. The QTF sensor also has a high quality factor for sensing capability of extremely small force. For this symposium, I will show how to investigate physical properties of the nanoscale condensed soft matters by using the QTF-AFM system having a high stiffness and high quality factor along with demonstration of nanofabrication & nonlinear sensor (applications).
Study of the Piezoelectric Properties of AlN Thin Films with PFM
1KETI (Korea Electronics Technology Institute), Smart sensor center
Seongngam-si, Kyunggi-do 13509, South Korea
(Fax: +82-(31)-789-7279 E-mail address: firstname.lastname@example.org)
In this paper, the piezoelectric properties of AlN thin films, that was fabricated by DC biased- voltage sputter, for MEMS applications (1-2) was studied by the PFM (piezoresponse force microscopy), TEM and Rocking curve measurement. The substrate of device was Si and the device cross section structure consisted of Si/SiO2/bottom Mo electrode/AlN/ top Mo electrode. AlN thin films were manufactured by DC magnetron sputtering method, especially by adding acceleration voltage to substrates to induce crystallization of AlN. This method was characterized by the ability to produce an AlN film at a low temperature (350°C) compatible with the CMOS process in the manufacture of smart sensors. The characteristics of PFM by various ALN fabrication processes were compared with TEM and Rocking Curve, and the piezo characteristics of AlN thin film were closely related to the phase characteristics of PFM, and these results were consistent with the results of TEM.
The characteristics of a device consisting of an aluminum nitride thin film can be seen after the device is manufactured. Therefore, it is impossible to predict the performance of the device due to the nature of the aluminum nitride thin film, which consumes money and time.
Through the methods and results of measurement of PFM conducted in this study, the piezoelectric properties of manufacturing AlN-based devices could be inferred from the performance of manufactured devices before the end of the total fabrication process.
Korea Research Institute of Standards and Science (KRISS), Korea
The nanoscopic resolution provided by atomic force microscopy (AFM) yields topographic images with exquisite detail, enabling visualization of individual atoms and intermolecular bonds under optimized conditions. Yet, it has proven difficult to relate the local interaction forces on which the contrast is based to chemically selective information. In this regard, recent developments in combining molecular excitations with mechanical force detection, photo-induced force microscopy (PiFM), are of particular interest, as these approaches seek to add chemical selectivity to force microscopy. This approach shows higher sensitivity and 1,000 times better spatial resolution than conventional ensemble averaged infrared microscopy, even under ambient and environmental conditions. High sensitivity and high spatial resolution are achieved via the strongly localized tip-enhanced force at the junction between the gold coated tip and the sample, which covers from induced dipole interaction to thermal expansion, by providing a spatial resolution of a few nanometers. The present study paves a new way to directly detect heterogeneous chemicals at the single component level, which is necessary to evaluate nanomaterial safety in biomedical applications.
Industrial AFM Research & Development, Park Systems Corp.
As the latest semiconductor process manufactures an ultra-fine pattern, In-line AFM technology is successfully adapted in the nanoscale structure measurement and defect review. Based on this AFM measurement, hybrid of measurement methods for achieving the highest performance and flexibility of process change are demanded. Since OLED process is emerging as the next generation display, AFM based OLED inspection tools is inevitable for miniaturizing and developing high density of OLED process.
In this field of cutting-edge technology, several items are issued as the Break-through point for pioneering cutting-edge methods: Miniature · Intelligence, Convergence · Complex, and Repeatability · Reproducibility. To comply for above key items, high level automation of measurement and stability during long time repeated usage are required. This nanoscale In-line AFM measurement technology has to be developed for maintaining this technology lead as a national competitiveness.
In this paper, we introduce development and implementation of inspection tool based on the In-line Hybrid AFM for optimizing fine patterning in semiconductor manufacturing process, OLED display and Micro-LED process.
Jake (Seong-Oh) Kim
Research Application Technology Center, Park Systems Corp.
Since atomic force microscopy (AFM) has been developed, it becomes novel technique for surface investigation including topography and other material properties measurement. AFM shows high utilization in the research field due to complementary relationships with optical microscopy, electron microscopy and other measuring equipment.
Kelvin Probe Force Microscopy (KPFM) is one of the well-known AFM modes that enables the monitoring of both surface morphology and surface potential distribution properties on a nanometer scale. KPFM has been utilized extensively to investigate the localized charge distributions on a surface layer, local surface potential distributions variations of surface work functions and ferroelectric domains, in a variety of research fields. Since the development of KPFM, it has become one of the more useful AFM options utilized by surface/material science and a variety of semiconductor industries. It is a unique technique for surface potential or work function mapping with nano-scale and their optional modes such as AM, Sideband, and Heterodyne have great advantages to explore a variety of material characterization with superior spatial resolution/improved electrical sensitivity.
In this study, we review overall information on KPFM including principle, optional modes, parameters, and application. In particular, we present results obtained with AM-KPFM, Sideband KPFM, and Heterodyne KPFM on well-defined samples with extended areas of different surface potentials. From these results, we directly compare the spatial resolution and image quality of AM-KPFM, Sideband KPFM, and Heterodyne KPFM under identical conditions.
Nguyen Dang Quang
Research Application Technology Center, Park Systems Corp.
(E-mail: email@example.com) Atomic force microscopy (AFM) has widely been used for understanding of mechanical properties in conjunction with surface structure and topography at the nano-scale. To probe the mechanical properties, a force-indentation curve can be obtained using the AFM. Then, information about mechanical properties can be determined from relationship between applied force by AFM probe and deformation of target sample based on contact mechanics model. However, it is not always straightforward to determine the mechanical properties from the force-indentation data obtained using the AFM. Conventional AFM probes have different geometries such as spherical, flat-ended, and conical shapes. Accordingly, the probe tips can be modeled with spherical, flat-punch, paraboloid, hyperboloid, or conical shapes, depending on the contact situation. Also, flexural stiffness (i.e., spring constant) of AFM cantilever should be carefully considered to apply sufficient force for measurable indentation depth. In addition, interfacial interactions (e.g., sliding friction) between the tip and sample surface may affect the force-indentation data. To model the contact between tip and sample, a contact mechanics model should be properly employed. In this regard, different factors should be considered such as adhesive interaction between tip and sample, and sample behavior under applied force by the tip (e.g., elastic, plastic, or viscoelastic behaviors). Hence, to improve the accuracy of nanomechanical properties measurements using AFM force-indentation curve, systematic approach based on understanding of the interaction between AFM probe and sample is considerably needed and is the scope of this work.