skip to main content

SciTech ConnectSciTech Connect

Title: Effect of dielectric stoichiometry and interface chemical state on band alignment between tantalum oxide and platinum

The tantalum oxide–platinum interface electronic properties determined by X-ray photoelectron spectroscopy are found to depend on the dielectric stoichiometry and platinum chemical state. We demonstrate the slow charging of the tantalum oxide in cases of Ta{sub 2}O{sub 5}/Pt and Ta{sub 2}O{sub 5−y}/Pt interfaces under the X-ray irradiation. This behavior is proposed to be related to the charge accumulation at oxygen vacancies induced traps. Based on the proposed methodology, we define the intrinsic conductive band offset (CBO) ∼1.3 eV (both for Ta{sub 2}O{sub 5}/Pt and Ta{sub 2}O{sub 5−y}/Pt) and CBO after the full saturation of the traps charging ∼0.5 eV, while the last one defines the energy position of charged traps below the bottom of conduction band. We demonstrate also the pining at the both Ta{sub 2}O{sub 5}/Pt and Ta{sub 2}O{sub 5−y}/Pt interfaces even in the “intrinsic” state, apparently induced by the presence of additional interfacial states. No shifts of Ta4f line and band alignment in over stoichiometric Ta{sub 2}O{sub 5+x}/Pt structure during X-ray irradiation, as well as the absence of pinning, resulting in increase of CBO up to 2.3 eV are found. This behavior is related to the PtO{sub 2} interfacing layer formation at Ta{sub 2}O{sub 5+x}/Pt, blocking the charging of the surfacemore » states and associated dipole formation.« less
Authors:
 [1] ;  [2] ; ; ;  [1]
  1. Moscow Institute of Physics and Technology, Institutskii lane 9, 141700 Dolgoprudny, Moscow Region (Russian Federation)
  2. (Moscow Engineering Physics Institute), Kashirskoye Shosse 31, 115409 Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
22482216
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BUILDUP; CHANNELING; CHEMICAL STATE; DIELECTRIC MATERIALS; DIPOLES; EV RANGE 01-10; INTERFACES; IRRADIATION; LAYERS; PLATINUM; PLATINUM OXIDES; STOICHIOMETRY; TANTALUM OXIDES; TRAPS; VACANCIES; X RADIATION; X-RAY PHOTOELECTRON SPECTROSCOPY