In-situ deposited HfO2and Y2O3on epi-Si/ p-Ge-a comparative study of the interfacial properties and reliability
Journal
Japanese Journal of Applied Physics
Journal Volume
61
Journal Issue
SC
Date Issued
2022
Author(s)
Abstract
Single-crystal Si films six-monolayers in thickness were epitaxially grown on Ge(001) surface to minimize the formation of undesirable GeOx with subsequent deposition of HfO2 and Y2O3. The interfacial properties and reliability of the in-situ deposited high-κ oxides on epi-Si/p-Ge(001) were compared. We have achieved interface trap density (Dit) values of (1-3) × 1011 eV-1cm-2 in the Y2O3/epi-Si/p-Ge(001), which are two times lower than those of the HfO2/epi-Si/p-Ge(001). The capacitance-equivalent-thicknesses under different annealing conditions were extracted to analyze the interdiffusion in the gate stacks under various thermal treatments. Y2O3/epi-Si/Ge exhibited higher thermal stability than HfO2/epi-Si/Ge. In both high-κ's gate stacks, the effective charge sheet densities (ΔNeff) are lower than the targeted value of 3 × 1010 cm-2. Compared to the Y2O3 gate stacks, attainment of a high acceleration factor of 11 in the HfO2 gate stacks suggested an improved defect-carrier decoupling in the latter stacks. © 2022 The Japan Society of Applied Physics.
Subjects
effective charge sheet density (ΔNeff); Ge; HFO2; high-k; interface trap density ( D); reliability; Y2O3
Other Subjects
Germanium; Hafnium oxides; Logic gates; Silicon wafers; Single crystals; Effective charge; Effective charge sheet density (ΔNeff); Gate stacks; Ge; High- k; Interface trap density; Interface trap density ( D); Interface-trap density; Interfacial reliability; Sheet density; Reliability
Type
journal article