Decomposition of the anisotropic strain in 3D-structure GaN layers using Raman spectroscopy

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Strain engineering in gallium nitride (GaN) is vital for improving optoelectronic and electronic devices.
• Miniaturization of GaN devices necessitates precise understanding of strain states.
• Current methods lack axial resolution for strain evaluation in microscale devices.

Purpose of the Study:

• To establish an axially resolved strain measurement technique for c-plane gallium nitride.
• To investigate the link between anisotropic strain and Raman peak splitting.
• To enable accurate strain decomposition in microarea devices.

Main Methods:

• Utilized Raman spectroscopy with specific polarized configurations ([Formula: see text] and [Formula: see text]).
• Induced anisotropic strain in 3D c-plane GaN structures via epitaxial lateral overgrowth.
• Analyzed the split Raman peaks to deduce the axial strain components.

Main Results:

• Demonstrated a correlation between anisotropic strain in c-plane GaN and Raman peak splitting.
• Successfully developed a method for axially decomposing strain in GaN using Raman spectroscopy.
• The technique is feasible with conventional Raman spectrometers and applicable to other wurtzite crystals.

Conclusions:

• A novel Raman spectroscopy-based technique for axially resolving strain in microarea wurtzite materials, including GaN, has been established.
• This method provides a new perspective for understanding complex strain states.
• Accurate strain comprehension will accelerate R&D of III-V semiconductor devices.