Linearized radially polarized light for improved precision in strain measurements using micro-Raman spectroscopy

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Strain engineering is critical for enhancing semiconductor transistor performance at the nanoscale.
• Raman spectroscopy offers a sensitive, non-invasive, and cost-effective method for in-line strain measurement.
• Current Raman spectroscopy strain measurements are routine but can be improved in accuracy and precision.

Purpose of the Study:

• To investigate the use of linearized radially polarized light for improved strain measurement accuracy in semiconductor devices.
• To quantitatively evaluate the enhanced sensitivity provided by this novel excitation source through numerical simulations.
• To benchmark the results against established transmission electron microscopy (TEM) techniques.

Main Methods:

• Utilized linearized radially polarized light as an excitation source for Raman spectroscopy.
• Performed numerical simulations to analyze electric field intensities and sensitivity enhancements.
• Compared Raman spectroscopy results with TEM diffraction-based techniques (nano-beam diffraction, Bessel diffraction).

Main Results:

• Linearized radially polarized light demonstrated significantly enhanced accuracy and precision compared to linearly polarized light.
• Numerical simulations confirmed increased electric field intensities contributing to improved sensitivity.
• Discrepancies with TEM results were attributed to strain relaxation during TEM sample preparation, highlighting Raman's advantage.

Conclusions:

• Linearized radially polarized light is a superior excitation source for Raman spectroscopy in semiconductor strain analysis.
• Raman spectroscopy, particularly with this advanced excitation, provides a non-destructive and accurate alternative to TEM for in-line strain testing.
• This technique is vital for advancing nanoscale semiconductor device development and manufacturing.