A broadband toolbox for scanning microwave microscopy transmission measurements

Abstract

In this paper, we present in detail the design, both electromagnetic and mechanical, the fabrication, and the test of the first prototype of a Scanning Microwave Microscope (SMM) suitable for a two-port transmission measurement, recording, and processing the high frequency transmission scattering parameter S21 passing through the investigated sample. The S21 toolbox is composed by a microwave emitter, placed below the sample, which excites an electromagnetic wave passing through the sample under test, and is collected by the cantilever used as the detector, electrically matched for high frequency measurements. This prototype enhances the actual capability of the instrument for a sub-surface imaging at the nanoscale. Moreover, it allows the study of the electromagnetic properties of the material under test obtained through the measurement of the reflection (S11) and transmission (S21) parameters at the same time. The SMM operates between 1 GHz and 20 GHz, current limit for the microwave matching of the cantilever, and the high frequency signal is recorded by means of a two-port Vector Network Analyzer, using both contact and no-contact modes of operation, the latter, especially minded for a fully nondestructive and topography-free characterization. This tool is an upgrade of the already established setup for the reflection mode S11 measurement. Actually, the proposed setup is able to give richer information in terms of scattering parameters, including amplitude and phase measurements, by means of the two-port arrangement.

Developments of Interfacial Measurement Using Cavity Scanning Microwave Microscopy

“…Scanning microwave microscopy has developed into a very broad research topic since its introduction and is favored by many researchers due to the nondestructive advantages of microwave testing [57][58][59]. It has now been successfully applied to characterize surface and subsurface samples at the nanoscale spatial resolution, exploring properties such as dielectric constant, doping concentration, and resistivity.…”

Developments and Recent Progresses in Microwave Impedance Microscope

“…62, the authors presented a rigorous modeling of nanosized SMM probes and their electrodynamic interaction with material samples at microwave frequencies [62]. They concluded that the SMM had the potential for use as a broadband dielectric spectroscopy operating at higher frequencies up to THz [63,64]. The numerical simulation is carried out by the finite element method (FEM).…”

Fabrication of oscillating metal probe for dynamic scanning microwave microscopy

“…This feature is particularly vital for conducting microwave characteristic testing in the fields of semiconductor devices and materials. [22][23][24] As a result, our research focuses on probe fabrication, microwave frequency tests, and imaging techniques to discern their potential applications in SMM testing technology.…”