In situ roughness measurements for the solar cell industry using an atomic force microscope

Area of Science:

• Materials Science
• Thin Film Technology
• Surface Metrology

Background:

• Areal roughness parameters are critical for thin film solar cell efficiency.
• Current quality control methods may be time-consuming or destructive.
• In situ monitoring is desirable for real-time process adjustments.

Purpose of the Study:

• To evaluate areal roughness parameters using portable atomic force microscopy in a fabrication setting.
• To validate this in situ measurement technique against laboratory standards.
• To assess the feasibility of 100% production testing for transparent conductive oxide.

Main Methods:

• Utilized a portable atomic force microscope (AFM) on a CNC diamond cutting machine.
• Measured areal roughness parameters on samples of transparent conductive oxide (TCO).
• Compared in situ measurements with those obtained under optimal laboratory conditions.

Main Results:

• Demonstrated good compatibility between in situ and laboratory-obtained areal roughness parameters.
• Fourier Spectral Analysis confirmed the reliability of the portable AFM measurements.
• The method allows for sample evaluation without damaging the TCO, enabling 100% testing.

Conclusions:

• Portable AFM is suitable for in situ quality control in thin film solar cell fabrication.
• This approach enhances measurement efficiency and production rates.
• The non-destructive nature of the method facilitates comprehensive quality assurance.