Speaker
Description
The continued downscaling of nanoelectronic devices, where performance is governed by nanometer accurate doping distributions, demands metrology solutions with matching spatial resolution. Scanning Spreading Resistance Microscopy (SSRM), an AFM based technique that measures the resistance as current spreads from a high pressure induced β tin phase of silicon beneath a conductive diamond tip, has met this need for over three decades [1]. The resulting spreading resistance is directly related to local resistivity, enabling reliable electrical characterization from lightly doped channel regions to heavily doped source/drain contacts. With calibration measurements on reference samples containing layers of known carrier concentration, spreading resistance maps can be converted into quantitative active carrier profiles, establishing SSRM as a key technique for carrier metrology.
In my talk, I will overview how SSRM has evolved from a two dimensional mapping method suitable for early planar transistors into a tomographic nanoscale sensing method, known as scalpel SSRM, capable of true 3D carrier mapping in state of the art device architectures such as FinFETs, nanosheet FETs, and complementary FETs. I will also discuss force modulated FFT SSRM, which addresses parasitic resistances inherent to confined device volumes and thereby significantly improves spreading resistance sensitivity. Beyond silicon CMOS, I will show how SSRM has been applied extensively to solar cell and III–V semiconductor characterization. The implementation of artificial intelligence for automated quantitative SSRM processing will be presented as an example case to demonstrate how AI can accelerate SSRM data analysis. Finally, I will highlight essential diamond probe technology advances for improvements in spatial resolution.
Looking ahead, I will introduce emerging concepts such as in situ SSRM integrated with FIB SEM TEM to facilitate site-specific analysis, and multi probe approaches that bridge the low pressure regime used for high resolution mapping with the high pressure regime required for tomographic imaging. Together, these developments sustain SSRM’s position as a powerful and versatile tool for probing nanoscale electrical information in future semiconductor technologies.
[1] M. A. R. Laskar, L. Wouters, P. Lagrain, J. Serron, N. Peric, A. Pondini, P. Eyben, T. Hantschel and U. Celano, Appl. Phys. Rev. 2025, 12, 041305.