Epitaxial growth of rutile TiO2 thin films by oxidation of TiN/Si{100} heterostructure. (15th January 2016)

• Record Type: Journal Article
• Authors: Moatti, A.; Bayati, R.; Narayan, J.
• Is Part Of: Acta materialia. Volume 103(2016)
• Page Start: 502
• Page End: 511
• Publication Date: 2016-01-15
• Subjects: Rutile -- Titanium oxide -- Titanium nitride -- Oxidation -- Epitaxy -- Thin films; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2015.10.022
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: We have integrated epitaxial TiO2 on a TiN/Si(100) platform through oxidation of TiN. The oxidation of TiN(100)/Si(100) results in the formation of an epitaxial rutile-TiO2 (r-TiO2 ) with a [110] out-of-plane orientation. We have studied in detail the r-TiO2 epitaxy and the epitaxial relationship is determined to be TiO2 (1 1 ¯ 0)||TiN(100) and TiO2 (110)||TiN(110). We rationalized this epitaxy using the domain matching epitaxy paradigm. Below the r-TiO2 epitaxial layer, we observed cuboids, which are mostly voids. We described the mechanism of oxidation where Ti out diffusion during oxidation leads to collapse of the nitrogen octahedron. This collapse makes neighboring Ti bonds weaker, promoting these Ti atoms to diffuse out next. Thus, cuboids filled with atomic nitrogen are formed, which then form N2 gas. The N2 pressure in these cuboids was estimated to be as high as 359 MPa, assuming all N2 is retained in the cuboids. This pressure can exceed the fracture stress of TiO2 and leads to rupture of thin TiO2 surface, which has been observed under certain conditions. Graphical abstract: