Quantitative three-dimensional carrier mapping in nanowire-based transistors using scanning spreading resistance...

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Nanoelectronic device performance relies heavily on charge carrier distribution.
• High-vacuum scanning spreading resistance microscopy (HV-SSRM) is a key 2D technique for carrier mapping.
• 3D carrier distribution is vital for understanding dopant mechanisms in nanoscale devices.

Purpose of the Study:

• To develop a quantitative 3D-carrier characterization technique.
• To extend the 2D capabilities of SSRM for 3D analysis.
• To support process development for next-generation nanoelectronic devices.

Main Methods:

• Acquired 2D carrier concentration maps on successive cross-sections of a nanowire (NW)-based heterojunction tunneling transistor.
• Arranged multiple devices in a staggered array for incremental cross-sections via a single cleave.
• Developed a specialized interpolation algorithm for reconstructing 3D carrier maps from 2D data, suitable for rotationally symmetric structures like NWs.

Main Results:

• Successfully extended SSRM from 2D to quantitative 3D-carrier profiling.
• Demonstrated the method on a SiGe-Si NW heterojunction tunneling transistor.
• Validated the 3D mapping by confirming the expected absence of carrier variation in the third dimension for NWs.

Conclusions:

• The presented approach enables high-resolution 3D-carrier mapping in nanoelectronic devices.
• This technique is essential for studying dopant distribution in confined 3D volumes.
• The developed methodology supports the advancement of semiconductor process development.