High-resolution scanning electron microscopy study of sputtered nanolaminated Ti/TiN multilayers

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Nanolaminated multilayers, such as Ti/TiN, are crucial in various technological applications.
• Accurate characterization of layer thickness and structure is essential for optimizing material properties.
• Traditional characterization methods may face limitations with nanoscale features.

Purpose of the Study:

• To investigate the morphologic and structural properties of nanolaminated Ti/TiN multilayers.
• To evaluate the effectiveness and complementarity of High-Resolution Scanning Electron Microscopy (HR-SEM) and X-ray Reflectometry (XRR) for multilayer characterization.
• To determine the precise layer thicknesses and periodicity of deposited Ti/TiN films.

Main Methods:

• Deposition of Ti/TiN multilayers on silicon substrates using reactive radio frequency (rf) sputtering.
• Morphologic and structural analysis using High-Resolution Scanning Electron Microscopy (HR-SEM) on cross-sections.
• Structural characterization and quantitative analysis using X-ray Reflectometry (XRR).

Main Results:

• For large periods (40 nm), HR-SEM provided clear images and accurate thickness measurements (Ti: 17 nm, TiN: 25 nm), while XRR patterns were less structured and difficult to simulate.
• For small periods (2.5 nm), XRR yielded intense, narrow Bragg peaks, enabling precise determination of a 2.6 nm period (Ti: 0.9 nm, TiN: 1.7 nm) through simulation.
• HR-SEM resolution (~2 nm) was insufficient to resolve the nanoscale layers in small-period multilayers.

Conclusions:

• HR-SEM and XRR are complementary techniques for characterizing nanolaminated Ti/TiN multilayers.
• The choice of technique depends on the multilayer period thickness.
• Accurate structural and morphologic data can be obtained for optimizing multilayer fabrication and performance.