FPGA-based reconfigurable scanning and data acquisition system for scanning electron microscopy.

Area of Science:

• Instrumentation
• Materials Science
• Physics

Background:

• Scanning Electron Microscopy (SEM) relies on precise scanning and data acquisition for high-resolution imaging.
• Existing SEM systems can be limited by data acquisition speed and signal-to-noise ratio (SNR).
• Hardware-level synchronization offers potential for enhanced performance in microscopy.

Purpose of the Study:

• To develop and evaluate an FPGA-based reconfigurable scanning and data acquisition system for SEM.
• To improve image quality and detail recovery in SEM by enhancing SNR and enabling faster acquisition.
• To demonstrate the system's modularity and applicability to various point-scanning instruments.

Main Methods:

• An FPGA (Xilinx Artix-7) was utilized for integrated raster scan waveform generation (14-bit DAC) and signal acquisition (12-bit ADC) with on-chip averaging.
• The system features real-time USB 2.0 High-Speed data streaming at 40 MB/s.
• Quantitative image quality benchmarks were performed using a grid-hole masking protocol and sub-pixel cross-correlation drift correction.

Main Results:

• The FPGA-based system achieved 41-47% higher spatial SNR compared to a commercial SEM.
• Near-theoretical temporal SNR scaling was observed, with a significant improvement over the commercial reference.
• Stable raster operation was demonstrated in fast-scan mode, producing clearly resolved secondary-electron images.

Conclusions:

• FPGA-based hardware synchronization significantly enhances practical recoverability of high-frequency spatial detail in SEM.
• The developed system offers substantial SNR improvements and enables high-quality imaging under reduced acquisition times.
• The modular architecture is adaptable for diverse point-scanning instruments beyond SEM.