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Title: Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO{sub 2}

Abstract

Pulsed low-energy (200 eV) ion-beam induced nucleation during Ge deposition on thin SiO{sub 2} film was used to form dense homogeneous arrays of Ge nanocrystals. The ion-beam action is shown to stimulate the nucleation of Ge nanocrystals when being applied after thin Ge layer deposition. Temperature and flux variation was used to optimize the nanocrystal size and array density required for memory device. Kinetic Monte Carlo simulation shows that ion impacts open an additional channel of atom displacement from a nanocrystal onto SiO{sub 2} surface. This results both in a decrease in the average nanocrystal size and in an increase in nanocrystal density.

Authors:
; ; ; ; ; ; ; ;  [1];  [2]
  1. Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, prospekt Lavrent'eva 13, 630090 Novosibirsk (Russian Federation)
  2. (Germany)
Publication Date:
OSTI Identifier:
20960185
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 90; Journal Issue: 13; Other Information: DOI: 10.1063/1.2719163; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPUTERIZED SIMULATION; CRYSTAL GROWTH; DEPOSITION; EV RANGE 100-1000; FILMS; GERMANIUM; ION BEAMS; LAYERS; MEMORY DEVICES; MOLECULAR BEAM EPITAXY; MONTE CARLO METHOD; NANOSTRUCTURES; NUCLEATION; SEMICONDUCTOR MATERIALS; SILICON OXIDES

Citation Formats

Stepina, N. P., Dvurechenskii, A. V., Armbrister, V. A., Kesler, V. G., Novikov, P. L., Gutakovskii, A. K., Kirienko, V. V., Smagina, Zh. V., Groetzschel, R., and Forschungszentrum Rossendorf, D-01328 Dresden. Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO{sub 2}. United States: N. p., 2007. Web. doi:10.1063/1.2719163.
Stepina, N. P., Dvurechenskii, A. V., Armbrister, V. A., Kesler, V. G., Novikov, P. L., Gutakovskii, A. K., Kirienko, V. V., Smagina, Zh. V., Groetzschel, R., & Forschungszentrum Rossendorf, D-01328 Dresden. Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO{sub 2}. United States. doi:10.1063/1.2719163.
Stepina, N. P., Dvurechenskii, A. V., Armbrister, V. A., Kesler, V. G., Novikov, P. L., Gutakovskii, A. K., Kirienko, V. V., Smagina, Zh. V., Groetzschel, R., and Forschungszentrum Rossendorf, D-01328 Dresden. Mon . "Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO{sub 2}". United States. doi:10.1063/1.2719163.
@article{osti_20960185,
title = {Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO{sub 2}},
author = {Stepina, N. P. and Dvurechenskii, A. V. and Armbrister, V. A. and Kesler, V. G. and Novikov, P. L. and Gutakovskii, A. K. and Kirienko, V. V. and Smagina, Zh. V. and Groetzschel, R. and Forschungszentrum Rossendorf, D-01328 Dresden},
abstractNote = {Pulsed low-energy (200 eV) ion-beam induced nucleation during Ge deposition on thin SiO{sub 2} film was used to form dense homogeneous arrays of Ge nanocrystals. The ion-beam action is shown to stimulate the nucleation of Ge nanocrystals when being applied after thin Ge layer deposition. Temperature and flux variation was used to optimize the nanocrystal size and array density required for memory device. Kinetic Monte Carlo simulation shows that ion impacts open an additional channel of atom displacement from a nanocrystal onto SiO{sub 2} surface. This results both in a decrease in the average nanocrystal size and in an increase in nanocrystal density.},
doi = {10.1063/1.2719163},
journal = {Applied Physics Letters},
number = 13,
volume = 90,
place = {United States},
year = {Mon Mar 26 00:00:00 EDT 2007},
month = {Mon Mar 26 00:00:00 EDT 2007}
}
  • Nanocrystals of group-IV semiconductor materials (Si, Ge, and SiGe) have been fabricated in SiO{sub 2} by ion implantation and subsequent thermal annealing. The microstructure of these nanocrystals has been studied by transmission electron microscopy. Critical influences of the annealing temperatures and implantation doses on the nanocrystal size distributions are demonstrated with the Ge-implanted systems. Significant roughening of the nanocrystals occurs when the annealing temperature is raised above the melting temperature of the implanted semiconductor material. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
  • The authors report the photon-induced conduction modulation in SiO{sub 2} thin films embedded with germanium nanocrystals (nc-Ge). The conduction of the oxide could be switched to a higher- or lower-conductance state by a ultraviolet (UV) illumination. The conduction modulation is caused by charging and discharging in the nc-Ge due to the UV illumination. If the charging process is dominant, the oxide conductance is reduced; however, if the discharging process is dominant, the oxide conductance is increased. As the conduction can be modulated by UV illumination, it could have potential applications in silicon-based optical memory devices.
  • Silicon dioxide (SiO{sub 2}) on Si layers with embedded germanium nanocrystals (Ge-ncs) were fabricated using Ge{sup +} implantation and subsequent annealing. Transmission electron microscopy and Rutherford backscattering spectrometry have been used to study the Ge redistribution in the SiO{sub 2} films as a function of annealing temperature. A monolayer of Ge-ncs near the Si/SiO{sub 2} interface was formed under specific annealing conditions. This layer, with a nc density and mean size measured to be, respectively, 1.1x10{sup 12}/cm{sup 2} and 5 nm, is located at approximately 4 nm from the Si/SiO{sub 2} interface. Capacitance-voltage measurements were performed on metal-oxide-semiconductor structures containingmore » such implanted SiO{sub 2} layers in order to study their electrical properties. The results indicate a strong memory effect at relatively low programming voltages (<5 V) due to the presence of Ge-ncs near the Si/SiO{sub 2} interface.« less
  • Metal-oxide-semiconductor structures containing Ge nanocrystals (NCs) of 3-4 nm diameter and 2x10{sup 12} cm{sup -2} density are shown to exhibit capacitance-voltage hysteresis of 20.9 V, one of the largest observed in Ge-NC based nonvolatile memories. The Ge NCs were fabricated in an oxide of 30 nm thickness by ion implantation with 30 keV Ge{sub 2}{sup -} ions to an equivalent fluence of 1x10{sup 16} Ge cm{sup -2} followed by annealing at 950 deg. C for 10 min. Secondary ion mass spectroscopy and transmission electron microscopy demonstrate the existence of Ge NCs whose average distance from the SiO{sub 2}/Si interface ismore » about 6.7 nm. It is shown that the memory effect is a likely consequence of charge trapping at Ge NCs and that it is enhanced by accurately controlling the distribution of Ge NCs with respect to the Si/SiO{sub 2} interface.« less
  • Finite-size effects become significant in nanoscale materials. When a nanocrystal is surrounded by a host matrix of a different nature, the perfection of the crystal structure is distorted by the interface formed between the nanocrystal and the matrix. The larger the surface-to-volume ratio of the nanocrystal, the higher the influence of the interface defect states on its properties. The presence of defect states in the interface can also explain the different responses of the nanocrystals (NCs) on external influences. By the combination of molecular-dynamics simulations and x-ray absorption spectroscopy measurements, we show that the amorphization of Si and Ge nanocrystalsmore » is reached at doses roughly one order of magnitude lower than those for the bulk crystals. Examining nanocrystals in the size range from 2.4 to 9 nm, we also show that the susceptibility to the amorphization decreases with increasing nanocrystal size. The finite-size effect remains significant also for the largest nanocrystals of 9 nm.« less