Development of a near-field scanning microwave microscope using a tunable resonance cavity for high resolution

Abstract

We report on the operational principles and the practical implementation of a near-field scanning microwave microscope system consisting of a λ/4 coaxial resonator with a tunable resonance cavity coupled to a sharp probe tip. The changes of sensitivity and spatial resolution as a function of cavity length are clearly modulated by tuning the resonance cavity. By tuning the resonance cavity, we demonstrate improved sensitivity and spatial resolution better than 4 µm of the near-field images of a YBa 2 Cu 3 O y thin film on a MgO substrate at an operating frequency of f = 1-1.5 GHz. We modelled the λ/4 coaxial resonator by a LCR circuit and the principles of operation can be explained by using perturbation theory, considering the radius of the probe tip, the quality factor, impedance matching, and the sample-tip distance.

Hard disk magnetic domain nano-spatial resolution imaging by using a near-field scanning microwave microscope with an AFM probe tip

“…There is also a need to develop tools to characterize magnetic imaging for submicron magnetic devices; this requires local measurement of magnetic properties such as magnetic permeability. Electromagnetic measurements using a near-field scanning microwave microscope (NSMM) has been emerging in the past few years to study electromagnetic properties with submicron resolution at microwave wavelengths [9][10][11][12][13]. To achieve such a goal, the probe tip of the NSMM has to be improved from the conventional metal tip and developed as a quantitative metrology tool with submicron resolution.…”

“…Fig. 1 (a) shows the experimental setup of the NSMM [13]. The AFM cantilever probe tip is presented on Fig.…”

Nondestructive characterization of surface resistance for copper(II) phthalocyanine thin films using a near-field scanning microwave microscope

“…Microwave scanning probes for local characterization of conducting films have attracted considerable interest since they are contactless, versatile, and provide high sensitivity. Recently, a variety of NSMM techniques with high sensitivity have been developed for the microwave-and millimeter-wave ranges [9][10][11][12][13][14][15][16]. Thus, NSMM can be used for the characterization of organic thin films.…”

Nondestructive characterization of various thin films using a near-field scanning millimeter-wave microscope

“…Recently, many groups have demonstrated a high spatial resolution and sensitive imaging technique using a near-field scanning microscope for the micro-and millimeter-wave range [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. For the millimeter-wave range, many groups have demonstrated an imaging technique using a nearfield millimeter-wave scanning microscope (NSMM) using a slit probe which showed a spatial resolution of about 30-100 mm [1][2][3][4][5][6][7][8][9][10][11][12].…”

“…For the millimeter-wave range, many groups have demonstrated an imaging technique using a nearfield millimeter-wave scanning microscope (NSMM) using a slit probe which showed a spatial resolution of about 30-100 mm [1][2][3][4][5][6][7][8][9][10][11][12]. Recently, instead of a slit probe, Kim et al [15] used a conventional metallic probe tip coupled to a waveguide resonator and demonstrated a spatial resolution better than 1 mm at f ¼ 60 GHz: The advantage of this system is its high Q-factor, which results in a high spatial resolution.…”