Abstract
Reactive ion etching was used to etch barium strontium titanate thin films in a CHF3/Ar plasma. BST surfaces before and after etching were analyzed by X-ray photoelectron spectroscopy to investigate the reaction ion etching mechanism, and chemical reactions had occurred between the F plasma and the Ba, Sr and Ti metal species. Fluorides of these metals were formed and remained on the surface during the etching process. Ti was almost completely removed because the TiF4 by-product is volatile. Minor quantities of Ti-F could still be detected by narrow scan X-ray photoelectron spectra, and Ti-F was thought to be present in the form of a metal-oxy-fluoride. These species were investigated from O1s spectra, and a fluoride-rich surface was formed during etching. BaF2 and SrF2 residues were difficult to remove because of their high boiling point. The etching rate was limited to 12.86 nm/min. C-F polymers were not found on the surface, indicating that the removal of BaF2 and SrF2 was important for further etching. A 1-min Ar/15 plasma physical sputtering was carried out for every 4 min of surface etching, which effectively removed remaining surface residue. Sequential chemical reaction and sputtered etching is an effective etching method for barium strontium titanate films.
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Gervais M, Gervais F, Champeaux C, et al. Strongly oriented BST films on La0.9Sr1.1NiO4 electrodes deposited on various substrates for integration of high capacitances on silicon. Appl Surf Sci, 2006, 252: 3085–3091
Gaillot D P, Zhao Q, Zhang F L, et al. Transparency cloak based on High-κ BST rods. Proceedings of the 38th EuMC, 2008. 869–872
Noda M, Inoue K, Zhu H, et al. Chopperless-operated dielectric bolometer mode of infrared image sensor with ferroelectric BST film using improved operation. IEEE I SAF, 2000, 2: 783–786
Belleville P, Bigarre J, Boy P, et al. Stable PZT sol for preparing reproducible high-permittivity perovskite-based thin films. J Sol-Gel Sci Techn, 2007, 43: 213–221
Ahamed F, Biggers R, Campbell A, et al. New research directions in tunable microwave dielectrics. Integr Ferroelectr, 2004, 66: 139–151
Challali F, Besland M P, Benzeggouta D, et al. Investigation of BST thin films deposited by RF magnetron sputtering in pure Argon. Thin Solid Films, 2010, 518: 4619–4622
Hu W C, Yang C R, Zhang W L, et al. Ferroelectric properties of Ba0.8Sr0.2TiO3 thin films prepared by RF magnetron sputtering. Integr Ferroelectr, 2006, 79: 131–138
Palathinkal T J, Cheng H F, Lee Y C, et al. Low loss tunable thick films based on (Ba,Sr)TiO3 and Ba4Ti13O30 materials. Integr Ferroelectr, 2004, 66: 213–221
Kim S B, Kim C-Il, Chang E G. Study on surface reaction of Ba,Sr.TiO3 thin films by high density plasma etching. J Vac Sci Technol A, 1999, 17: 2156–2161
Stafford L, Margot J, Langlois O. Barium-strontium-titanate etching characteristics in chlorinated discharges. J Vac Sci Technol A, 2003, 21: 1247–1252
Kim S B, Lee Y H, Kim T H, et al. Etching mechanism of Ba,Sr.TiO3 films in high density Cl2/BCl3/Ar plasma. J Vac Sci Technol A, 2000, 18: 1381–1384
Choi S K, Kim D P, Kim C-II, et al. Damage in etching of Ba,Sr.TiO3 thin films using inductively coupled plasma. J Vac Sci Technol A, 2001, 19: 1063–1067
Kim G H, Kim K T, Kim C-II. Dry etching of Ba,Sr.TiO3 thin films using an inductively coupled plasma. J Vac Sci Technol A, 2005, 23: 894–897
Zhang B, Quan Z C, Zhang T J, et al. Effect of oxygen gas and annealing treatment for magnetically enhanced reactive ion etched (Ba0.65,Sr0.35)TiO3 thin films. J Appl Phys, 2007, 101: 014107(1–8)
Shibano T, Takenaga T, Nakamura K, et al. Etching of Ba,Sr.TiO3 film by chlorine plasma. J Vac Sci Technol A, 2000, 18: 2080–2084
Wu D S, Lin C C, Horng R H, et al. Etching characteristics and plasma-induced damage of high-k Ba0.5Sr0.5TiO3 thin-film capacitors. J Vac Sci Technol B, 2001, 19: 2231–2236
Kang P S, Kim K T, Kim D P, et al. Study of damage reduction of Ba0.6,Sr0.4.TiO3 thin films etched in Ar/CF4 plasmas. J Vac Sci Technol A, 2003, 21: 1469–1474
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Dai, L., Wang, S., Shu, P. et al. Etching mechanism of barium strontium titanate (BST) thin films in CHF3/Ar plasma. Chin. Sci. Bull. 56, 2267–2271 (2011). https://doi.org/10.1007/s11434-011-4561-5
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DOI: https://doi.org/10.1007/s11434-011-4561-5