Kangguo Cheng, Chanro Park, et al.
VLSI Technology 2020
In-line Raman spectroscopy for compositional and strain metrology throughout front-end-of-line (FEOL) manufacturing of next-generation gate-all-around nanosheet field-effect transistors is presented. Thin and alternating layers of fully strained pseudomorphic Si(1 - x)Gex and Si were grown epitaxially on a Si substrate and subsequently patterned. Intentional strain variations were introduced by changing the Ge content (x = 0.25, 0.35, 0.50). Polarization-dependent in-line Raman spectroscopy was employed to characterize and quantify the strain evolution of Si and Si(1 - x)Gex nanosheets throughout FEOL processing by focusing on the analysis of Si-Si and Si-Ge optical phonon modes. To evaluate the accuracy of the Raman metrology results, strain reference data were acquired by non-destructive high-resolution x-ray diffraction and from destructive lattice deformation maps using precession electron diffraction. It was found that the germanium-alloy composition as well as Si and Si(1 - x)Gex strain obtained by Raman spectroscopy are in very good agreement with reference metrology and follow trends of previously published simulations.
Kangguo Cheng, Chanro Park, et al.
VLSI Technology 2020
G. Tsutsui, C. Durfee, et al.
VLSI Technology 2018
Ashish Ranjan
DAC 2025
Daniel Schmidt
PMI Symposium 2025