Scanning microwave microscopy applied to semiconducting GaAs structures

Abstract

A calibration algorithm based on one-port vector network analyzer (VNA) calibration for scanning microwave microscopes (SMMs) is presented and used to extract quantitative carrier densities from a semiconducting n-doped GaAs multilayer sample. This robust and versatile algorithm is instrument and frequency independent, as we demonstrate by analyzing experimental data from two different, cantilever- and tuning fork-based, microscope setups operating in a wide frequency range up to 27.5 GHz. To benchmark the SMM results, comparison with secondary ion mass spectrometry is undertaken. Furthermore, we show SMM data on a GaAs p-n junction distinguishing p- and n-doped layers.

Fabrication and Measurements of Inductive Devices for Scanning Microwave Microscopy

“…Then, a combination of plasma etching process and Bosch process took place to etch away Si material in this window. As reported in [6], the SMM tip can sense the inhomogeneity of dopant density of the underneath substrate. As the dopant density of our Si substrate varies between 3.3×10 16 -2.9×10 17 cm −3 , as calculated from its resistivity (0.1-0.5 Ω•cm), the removal of Si material reduces the uncertainty of our measurements on fabricated devices.…”

“…While measurements were performed under ambient conditions, the humidity and the temperature are controlled. More details about our setup can be found in [6].…”

“…Scanning microwave microscopy (SMM) is still a rather new member of the family of scanning probe techniques, but it has been applied successfully to the analysis of a wide range of materials [1]- [6]. The basic working principle is to send a microwave signal to the SMM tip and to measure the reflected fraction.…”

“…Then, values of these error coefficients can be calculated using S 11 obtained for three samples with known impedance and the extraction of impedance of unknown devices can be performed. Later, the mSOL technique has been employed successfully in SMM measurements for ndoped GaAs samples [6].…”

Near-Field Scanning Millimeter-Wave Microscope Operating Inside a Scanning Electron Microscope: Towards Quantitative Electrical Nanocharacterization

“…The spatial resolution is therefore mainly governed by geometry. SMM has received a growing interest from the research community to address a wide range of applications, including semiconductor materials such as 1D and 2D materials [14][15][16][17], biology [18][19][20][21][22][23][24][25], quantum physics [26][27][28][29][30] or energy materials [31][32][33]. There is an urgent need to develop SMM traceability to yield quantitative and calibrated data.…”