3D spatial resolution improvement by dual-axis electron tomography: application to tri-gate transistors

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Semiconductor device performance is critically dependent on structural geometry and variations.
• The gate stack geometry is particularly crucial for the performance of transistors.
• Accurate characterization of nanoscale structures is essential for advancing semiconductor technology.

Purpose of the Study:

• To investigate the gate stack geometry of a tri-gate transistor.
• To demonstrate the enhanced resolution capabilities of dual-axis electron tomography for nanoscale device characterization.
• To showcase dual-axis tomography as a valuable tool for measuring local gate oxide thickness.

Main Methods:

• Utilized dual-axis electron tomography for high-resolution 3D reconstruction of the transistor gate.
• Performed simulations and experimental studies to validate the methodology.
• Applied the technique to measure the local thickness of the gate oxide.

Main Results:

• Achieved high-resolution reconstruction of all surfaces of the tri-gate transistor gate.
• Successfully measured the local thickness of the gate oxide.
• Demonstrated that dual-axis tomography improves reconstruction resolution, even without significant missing wedge artifacts.

Conclusions:

• Dual-axis electron tomography offers superior resolution for nanoscale device characterization.
• This method provides accurate measurements of critical dimensions like gate oxide thickness.
• The technique is versatile, requires no prior information, and is extensible to multiple tilt axes.