XAFS and TEM Investigation of Nanocluster Formation in 64 Zn + Ion-Implanted and Thermo-Oxidized SiO 2 Film
- PDF / 1,932,968 Bytes
- 6 Pages / 593.972 x 792 pts Page_size
- 99 Downloads / 158 Views
https://doi.org/10.1007/s11664-020-08454-7 Ó 2020 The Minerals, Metals & Materials Society
XAFS and TEM Investigation of Nanocluster Formation in 64Zn+ Ion-Implanted and Thermo-Oxidized SiO2 Film E.V. KHRAMOV,1 V.V. PRIVEZENTSEV,2,3,6 A.N. PALAGUSHKIN,3 K.D. SHCHERBACHEV,4 and N.YU. TABACHKOVA4,5 1.—National Research Center ‘‘Kurchatov Institute’’, Moscow, Russia 123182. 2.—Federal Research Center ‘‘Institute for System Analysis, Russian Academy of Sciences’’, Moscow, Russia 117218. 3.—Valiev Institute of Physics and Technology, Russian Academy of Sciences, Moscow, Russia 117218. 4.—National Research Technological University ‘‘MISiS’’, Moscow, Russia 119049. 5.—Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov Str. 38, Moscow, Russia 119991. 6.—e-mail: [email protected]
Due to their tunable current–voltage characteristics, Zn-doped thin SiO2 films are promising for microelectronic devices, e.g., memristors. In this work we studied single-crystal Si (100) substrates with 200 nm SiO2 surface layers implanted with 64Zn+ using Zn K-edge x-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM) and electron diffraction. We used two specimens: as-implanted and annealed in oxygen at 700°C. Cross-section TEM analysis showed that 64Zn+ implantation leads to the formation of a subsurface layer consisting of Zn nanoparticles approximately 7 nm in size. The nanoparticles are distributed in depths from 10 nm to 90 nm, with a concentration peak at 45 nm. Electron microscopy showed that most of the Zn nanoparticles are amorphous. However, XAS data indicated that almost all the Zn atoms are coordinated with oxygen. Thus, only a small fraction of zinc atoms are involved in the formation of nanoclusters. Annealing at 700°C leads to the oxidation of particles with the formation of the Zn2SiO4 phase. The particle sizes in the surface layer of SiO2 after annealing vary from 3 nm to 20 nm. Key words: SiO2 film, ion implantation, thermal oxidation, Zn, ZnO, nanoclusters, XAFS, TEM
INTRODUCTION Electric field-induced resistive switching has been studied for many materials.1–3 Along with their simple geometry and a wide choice of materials (NiO, TiO, HfO2), metal-oxide-based random access memory (ReRAM) cells have high speed, e.g., fast switching speeds of several nanoseconds, low operating current of the order of nA, scalability in the nanometer range and a potential storage capacity of several bits.4–6 It was shown that thin films of SiOxdoped amorphous Zn (so-called SZO films) are promising due to the compatibility of the SZO and
(Received March 17, 2020; accepted August 25, 2020)
CMOS technologies.7 SZO films were reported to have various current–voltage characteristics, from diode to memristor ones, depending on the concentration of Zn or ZnOx nanoclusters and the DC voltage applied.7 A hypothetical explanation for this non-trivial behavior of the Zn@SZO system is the formation of defects induced by Zn or ZnOx clusters.8 Therefore, it is necessary to study not only the current–voltag
Data Loading...
