Polarized cathodoluminescence for strain measurement

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Semiconductor material properties are significantly influenced by strain.
• Selecting appropriate strain measurement techniques involves balancing sensitivity, resolution, and field of view.
• Existing methods may not offer the desired combination of these parameters.

Purpose of the Study:

• To introduce and validate a novel strain measurement technique using the degree of polarization of cathodoluminescence (CL).
• To demonstrate the technique's capabilities in terms of sensitivity, resolution, and field of view.
• To present a method that provides strain information complementary to CL spectroscopy.

Main Methods:

• Utilizing the degree of polarization of cathodoluminescence (CL) as the primary measurement.
• Developing a detailed experimental setup and data treatment procedure for CL polarization analysis.
• Testing the technique on cross-sections of bulk indium phosphide (InP) samples subjected to strain via a patterned hard mask.

Main Results:

• The developed CL polarization technique exhibits excellent sensitivity (10^-5) and intermediate resolution (approx. 100 nm).
• The field of view is adjustable, offering flexibility in analysis.
• Strain information obtained is complementary to that from CL spectroscopy, enhancing characterization capabilities.

Conclusions:

• The degree of polarization of cathodoluminescence is a viable and sensitive method for strain measurement in semiconductors.
• This technique offers a valuable alternative or complement to existing methods, particularly for materials like indium phosphide.
• Further refinement of the technique and exploration of its limitations are warranted for broader applications.