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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Relationships among growth mechanism, structure and morphology of PEALD TiO2 films: the influence of O-2 plasma power, precursor chemistry and plasma exposure mode

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Chiappim, W. [1, 2] ; Testoni, G. E. [1, 2] ; Doria, A. C. O. C. [1] ; Pessoa, R. S. [1, 2] ; Fraga, M. A. [3] ; Galvao, N. K. A. M. [2] ; Grigorov, K. G. [4] ; Vieira, L. [1, 2] ; Maciel, H. S. [1, 2]
Total Authors: 9
[1] Univ Vale Paraiba Univap, Nanotechnol & Plasmas Proc Lab, BR-12244000 Sao Jose Dos Campos, SP - Brazil
[2] Inst Tecnol Aeronaut ITA DCTA, Plasma & Proc Lab, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[3] INPE, Associate Lab Sensors & Mat, BR-12227010 Sao Jose Dos Campos, SP - Brazil
[4] Space Res & Technol Inst, Acad G Bonchev Str Bl-1, Sofia 1113 - Bulgaria
Total Affiliations: 4
Document type: Journal article
Source: Nanotechnology; v. 27, n. 30 JUL 29 2016.
Web of Science Citations: 8

Titanium dioxide (TiO2) thin films have generated considerable interest over recent years, because they are functional materials suitable for a wide range of applications. The efficient use of the outstanding functional properties of these films relies strongly on their basic characteristics, such as structure and morphology, which are affected by deposition parameters. Here, we report on the influence of plasma power and precursor chemistry on the growth kinetics, structure and morphology of TiO2 thin films grown on Si(100) by plasma-enhanced atomic layer deposition (PEALD). For this, remote capacitively coupled 13.56 MHz oxygen plasma was used to act as a co-reactant during the ALD process using two different metal precursors: titanium tetrachloride (TiCl4) and titanium tetraisopropoxide (TTIP). Furthermore, we investigate the effect of direct plasma exposure during the co-reactant pulse on the aforementioned material properties. The extensive characterization of TiO2 films using Rutherford backscattering spectroscopy, ellipsometry, x-ray diffraction (XRD), field-emission scanning electron microscopy, and atomic force microscopy (AFM) have revealed how the investigated process parameters affect their growth per cycle (GPC), crystallization and morphology. The GPC tends to increase with plasma power for both precursors, however, for the TTIP precursor, it starts decreasing when the plasma power is greater than 100 W. From XRD analysis, we found a good correlation between film crystallinity and GPC behavior, mainly for the TTIP process. The AFM images indicated the formation of films with grain size higher than film thickness (grain size/film thickness ratio approximate to 20) for both precursors, and plasma power analysis allows us to infer that this phenomenon can be directly related to the increase of the flux of energetic oxygen species on the substrate/growing film surface. Finally, the effect of direct plasma exposure on film structure and morphology was evidenced showing that the grid removal causes a drastic reduction in the grain size, particularly for TiO2 synthesized using TiCl4. (AU)

FAPESP's process: 11/50773-0 - Center of excellence in physics and applications of plasmas
Grantee:Ricardo Magnus Osório Galvão
Support type: Research Projects - Thematic Grants
FAPESP's process: 15/05956-0 - 15th International Conference on Atomic Layer Deposition
Grantee:Rodrigo Savio Pessoa
Support type: Research Grants - Meeting - Abroad
FAPESP's process: 15/10876-6 - Plasma-fungal biofilm interaction: diagnostic of the plasma and inactivation process of the Candida spp strains
Grantee:Anelise Cristina Osorio Cesar Doria
Support type: Scholarships in Brazil - Doctorate