Scanning microwave microscopy applied to semiconducting GaAs structures

Area of Science:

• Materials Science
• Physics
• Electrical Engineering

Background:

• Scanning Microwave Microscopy (SMM) enables nanoscale material characterization.
• Accurate quantitative analysis requires robust calibration methods.
• Previous SMM calibration techniques lacked versatility and independence.

Purpose of the Study:

• To develop and validate a novel, instrument- and frequency-independent calibration algorithm for SMM.
• To extract quantitative carrier densities from semiconductor samples using SMM.
• To demonstrate the algorithm's applicability across different SMM setups and frequencies.

Main Methods:

• A one-port vector network analyzer (VNA) calibration algorithm was developed for SMM.
• The algorithm was applied to an n-doped GaAs multilayer sample.
• Experimental data were acquired using two distinct SMM setups (cantilever- and tuning fork-based) up to 27.5 GHz.
• SMM results were benchmarked against Secondary Ion Mass Spectrometry (SIMS).

Main Results:

• Quantitative carrier densities were successfully extracted from the GaAs sample.
• The calibration algorithm demonstrated robustness and versatility across different SMM configurations.
• The algorithm proved independent of specific instrument parameters and operating frequency.
• SMM data successfully distinguished between p- and n-doped layers in a GaAs p-n junction.

Conclusions:

• The presented VNA-based calibration algorithm significantly enhances the quantitative capabilities of SMM.
• This method provides a reliable approach for nanoscale carrier density profiling in semiconductors.
• The algorithm's independence allows for broad applicability in materials research and device analysis.