Atom-probe for FinFET dopant characterization.

Area of Science:

• Semiconductor Device Physics
• Materials Science
• Nanotechnology

Background:

• Moore's Law and ITRS goals drive the development of advanced transistor architectures like FinFETs.
• FinFET performance relies heavily on precise control of dopant distribution in 3D.
• Existing metrology techniques lack the necessary 3D nanometer precision for characterizing dopant profiles in FinFETs.

Purpose of the Study:

• To develop and present a methodology for studying FinFET structures using Atom Probe Tomography (APT).
• To address challenges in preparing and locating invisible FinFET structures for APT analysis.
• To quantitatively compare APT findings on dopant implantation angles with Secondary Ion Mass Spectrometry (SIMS) and theoretical models.

Main Methods:

• Utilizing Atom Probe Tomography (APT) for 3D nanoscale dopant distribution analysis.
• Developing novel sample preparation techniques for FinFETs, overcoming challenges with invisible structures.
• Employing focused ion beam (FIB) and scanning electron microscopy (SEM) for locating and positioning samples.
• Comparing APT results with 1D SIMS and theoretical models for dopant profiles.

Main Results:

• Demonstrated successful APT analysis of FinFET structures, achieving sub-nanometer resolution in 3D.
• Presented effective strategies for preparing and locating FinFETs, even when invisible in standard imaging.
• Provided quantitative insights into the impact of different dopant implantation angles (10° and 45°) on conformal doping.
• Established a quantitative comparison between APT, SIMS, and theoretical doping models.

Conclusions:

• APT is a powerful technique for 3D dopant profiling in advanced FinFET devices.
• The presented methodology enables the analysis of previously challenging FinFET structures.
• Understanding dopant distribution is crucial for optimizing FinFET performance and device design.