Effect of Process Temperature and Reaction Cycle Number on Atomic Layer Deposition of TiO2 Thin Films Using TiCl4 and H2O Precursors: Correlation Between Material Properties and Process Environment

Author(s)

Chiappim, W. ^{[1, 2]} ; Testoni, G. E. ^{[1, 2]} ; de Lima, J. S. B. ^[1] ; Medeiros, H. S. ^[2] ; Pessoa, Rodrigo Savio ^{[1, 2]} ; Grigorov, K. G. ^[3] ; Vieira, L. ^{[1, 2]} ; Maciel, H. S. ^{[1, 2]}

Affiliation

^[1] Univ Vale Paraiba Univap, Nanotechnol & Plasmas Proc Lab, BR-12244000 Sao Jose Dos Campos, SP - Brazil

^[2] ITA, DCTA, Plasma & Proc Lab, BR-12228900 Sao Jose Dos Campos, SP - Brazil

^[3] Space Res & Technol Inst, Sofia 1113 - Bulgaria

• Document type: Journal article
• Source: Brazilian Journal of Physics; v. 46, n. 1, p. 56-69, FEB 2016.
• Web of Science Citations: 11

Abstract

The effect of process temperature and reaction cycle number on atomic layer-deposited TiO2 thin films onto Si(100) using TiCl4 and H2O precursors was investigated in order to discuss the correlation between the growth per cycle (GPC), film structure (crystallinity), and surface roughness as well as the dependence of some of these properties with gas phase environment such as HCl by-product. In this work, these correlations were studied for two conditions: (i) process temperatures in the range of 100-500 degrees C during 1000 reaction cycles and (ii) number of cycles in the range of 100-2000 for a fixed temperature of 250 degrees C. To investigate the material properties, Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GIXRD), and atomic force microscopy (AFM) techniques were used. Mass spectrometry technique was used to investigate the time evolution of gas phase species HCl and H2O during ALD process. Results indicate that the GPC does not correlate well with film crystallinity and surface roughness for the evaluated process parameters. Basically, the film crystallinity relies solely on grain growth kinetics of the material. This occurs due to higher HCl by-product content during each purge step. Furthermore, for films deposited at variable cycle number, the evolution of film thickness and elemental composition is altered from an initial amorphous structure to a near stoichiometric TiO2-x and, subsequently, becomes fully stoichiometric TiO2 at 400 cycles or above. At this cycle value, the GIXRD spectrum indicates the formation of (101) anatase orientation. (AU)

• FAPESP's process: 11/50773-0 - Center of excellence in physics and applications of plasmas
• Grantee: Ricardo Magnus Osório Galvão
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/05956-0 - 15th International Conference on Atomic Layer Deposition
• Grantee: Rodrigo Savio Pessoa
• Support Opportunities: Research Grants - Meeting - Abroad