Defects responsible for the Fermi level pinning in n+ poly-Si/HfO2 gate stacks
作者： Byungki Ryu , K. J. Chang
DOI: 10.1063/1.3527929
关键词: Amorphous solid 、 Condensed matter physics 、 Quasi Fermi level 、 Fermi level 、 Density functional theory 、 Electrode 、 Silicon 、 Dimer 、 Oxide 、 Materials science
摘要: Based on density functional calculations, we propose a defect model that can explain flat band voltage shifts, especially in n+ poly-Si/HfO2 gate stacks. For two interface structures, with Si electrodes top of crystalline and amorphous HfO2, find the formation O-vacancies at interface, which exhibit weak Si–Si dimer bonds low energies, very different from those oxide. Due to bonds, charge trap levels lie near conduction edge, leading Fermi level pinning shifts poly-Si electrodes.
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