Cross-sectional high-resolution transmission electron microscopy (HR-TEM) image of a sub- EOT gate stack (see Ref. 7) showing no apparent interfacial layer between the atomically abrupt high- dielectric and the substrate.
sample surface root-mean-square roughness measured by atomic force microscopy (AFM) as a function of the etch time in 100:1 aqueous HF solution.
(a) Evolution of the Ge core-level SR-PES spectra as a function of the stack wet-etching time taken at a photon energy of . (b) Scaled and zoomed spectra after 3, 6, and of etch disclosing the embedded Zr core-level signals of similar binding energy.
Peak-fitted SR-PES spectra from the stack after of etch with both elemental and oxidized Ge peaks assigned.
Extracted core-level Ge fitted peak areas as a function of etch time. Cross-sectional schematics of the stack are also included to illustrate the layer-by-layer etching progress.
Illustrations of escape depth calculation of the photoelectrons from Ge substrate at two different time points: (i) right around the complete removal and (ii) right around the complete removal.
(a) Valence-band photoemission spectra from thicker captured during the etching evolution. (b) Valence-band spectra (left) from a clean bulk Ge sample and the stack after of etch with their corresponding Ge core-level peaks aligned (right).
Energy-band diagram of the structure inferred from the SR-PES measurements.
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