Eur. Phys. J. B (2013) 86: 336
https://doi.org/10.1140/epjb/e2013-40124-2

Regular Article

Charge storage behavior of nanostructures based on SiGe nanocrystals embedded in Al₂O₃ matrix

¹ Centre of Physics, University of Minho, 4710-057 Braga, Portugal
² Departamento de Ciências dos Materiais/CENIMAT I3N, FCT, Universidade Nova Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
³ Rudjer Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb, Croatia
⁴ Elettra-Sincrotrone Trieste, 34149 Basovizza, Italy
⁵ Physics Department, University of Lisbon and ICEMS, 1749-016 Lisboa, Portugal
⁶ Faculty of Sciences and Techniques, Physics Department, Abdelmalek Essaadi University, BP 416, Tangier, Morocco

^a e-mail: levichev@fisica.uminho.pt

Received: 13 February 2013
Received in final form: 8 May 2013
Published online: 30 July 2013

Abstract

The charge storage behavior of nanostructures based on Si_1−xGe_x (0 ≤ x ≤ 1) nanocrystals (NCs) in an Al₂O₃ matrix was investigated. The structures have been grown by RF magnetron sputtering and subsequently annealed at temperatures ranging from 700 °C to 1000 °C for 30 min in nitrogen ambient. The stoichiometry of the SiGe NCs and the alumina crystalline structure were found to be significantly dependent on the RF power and the annealing temperature. The sizes of the SiGe NCs and their distribution were investigated by grazing incidence small angle X-ray scattering (GISAXS). The capacitance-voltage (C-V) and conductance-voltage (G-V) measurements were performed to investigate the charge trapping characteristics of the memory structures. The C-V hysteresis width depends on variations in the crystalline structure resulting from different annealing temperatures. It is also shown that charge injection is governed by the Fowler-Nordheim tunnel mechanism for higher electric fields.