Carrier Mapping in Sub-2nm Node Nanosheet Transistors with Scanning Spreading Resistance Microscopy
Andrea Pondini1,2, Pierre Eyben1, Lennaert Wouters1
1IMEC vzw, Leuven, Belgium.
Small Methods
|February 11, 2026
Summary
Advanced scanning spreading resistance microscopy (SSRM) now maps active carriers in nanosheet channels for next-gen transistors. This breakthrough aids precise junction engineering in gate-all-around devices.
Area of Science:
- Semiconductor device physics
- Materials characterization
- Nanotechnology
Background:
- Gate-all-around (GAA) architectures like Nanosheet FETs (NSFETs) are crucial for 2nm nodes and beyond.
- Controlling parasitic resistance requires precise junction engineering.
- Nanometer-scale carrier mapping is essential for advanced semiconductor characterization.
Purpose of the Study:
- To demonstrate an advancement in Scanning Spreading Resistance Microscopy (SSRM) for carrier mapping in nanosheet channels.
- To enable carrier profiling with nanometer-scale resolution in ultra-thin nanosheet channels.
- To validate SSRM's utility for junction engineering in GAA devices.
Main Methods:
- Optimized sample preparation for sub-nanometer topography.
- Utilized ultra-sharp diamond probes for high-resolution measurements.
- Implemented a linear current amplifier to mitigate logarithmic amplifier artifacts.
Main Results:
- Achieved SSRM carrier mapping in 5.5 nm thick nanosheet channels.
- Observed increased phosphorus diffusion after a 950°C rapid thermal anneal.
- Carrier profiles showed excellent agreement with Kinetic Monte Carlo simulations.
Conclusions:
- SSRM has been significantly advanced for carrier mapping in NSFETs.
- The technique provides direct feedback on junction formation in GAA devices.
- Optimized SSRM is a valuable tool for semiconductor process development.
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