Work function extraction of metal gates with alternate channel materials
(Color online) Schematics of HfSiO2/SiO2/SiGe/p-Si stack.
Schematic band diagrams of the SiGe/p-Si heterojunction with Si substrate Boron doping concentrations of (a) 1 × 1015 cm−3 and (b) 1 × 1019 cm−3 at Vg = 0 V. The depletion region is shaded.
Dependence of the Si and SiGe Surface Potentials on the (a) doping concentration of Si for the TiN/HfO2/SiO2/SiGe with a SiGe thickness of 40 nm and (b) thickness of SiGe for the TiN/HfO2/SiO2/SiGe with a doping concentration of Na = 1 × 1015/cm3 and 1 × 1017/cm3. All simulations were run using a HfO2 thickness of 6 nm.
Flatband voltage vs EOT for effective work function extraction of devices with fixed interfacial SiO2 layer, varying HfSiO2 layers and a TiN contact thickness of (a) 3 nm and (b) 20 nm.
C-V curve corresponding to a specific EOT device with a heterojunction plotted against a simulated device with the same EOT without a heterojunction using SiGe as the substrate.
Tabulation of charges potentially affecting the flat band voltage including the symbols used to represent the charges throughout the paper along with assumptions regarding the charges explained within the paper.
Tabulation of charges located at the HfSiO2/SiO2 interface, SiO2/Si interface + permittivity of SiGe multiplied by the surface perpendicular electric field of SiGe and the extracted effective work function values using Eq. (4) using different values for the intrinsic concentrations. This analysis indicates that the calculated effective work function is within 5% of the reference.
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