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Characterization of Tin(IV) Oxide Thin Films Prepared by Atmospheric Pressure Chemical Vapor Deposition of cis ‐[SnCl 4 {OC(H)OC 2 H 5 } 2 ]
Author(s) -
Talaty Nari N.,
Beck Kristina,
Citeau Helene,
Kirschbaum Kristin,
Giolando Dean M.
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200800394
Subject(s) - tin , tin oxide , chemical vapor deposition , thin film , analytical chemistry (journal) , oxide , substrate (aquarium) , reagent , atmospheric pressure , deposition (geology) , silicon tetrachloride , materials science , chemistry , inorganic chemistry , nanotechnology , organic chemistry , silicon , metallurgy , paleontology , oceanography , sediment , geology , biology
A new single‐source precursor, [SnCl 4 {OC(H)OC 2 H 5 } 2 ], prepared by treating tin tetrachloride with ethyl formate (1:2 ratio) was developed for the deposition of tin oxide thin films on glass substrates. The compound [SnCl 4 {OC(H)OC 2 H 5 } 2 ] is highly volatile and provides very high growth rates (up to 100Å s −1 at 560 °C) in an atmospheric pressure chemical vapor deposition (APCVD) reactor. More significantly, the compound does not decompose to tin oxide below 320 °C, thereby minimizing the formation of particles in the vapor above the growing tin oxide film. To prepare highly conducting fluorine doped tin oxide (SnO 2 :F) films 2,2,2‐trifluoroethyl trifluoroacetate was used as the source of fluoride. High quality SnO 2 :F films were deposited at 560 °C with a flow rate of 2 mL fluoride reagent hr −1 ; typical film properties are resistivity of 5.9 X 10 −4 Ω cm, Hall mobility of 27.3 cm 2 V −1 s −1 , carrier concentration of 3.9 X 10 20 cm −3 and percent transmission ranging from 86 to 88 %. The best films of SnO 2 :F possess transparencies as high as 90 % (750 nm), sheet resistances as low as 7 Ω sq −1 and Haacke's figure of merit as high as 29 X 10 −3 (750 nm). The newly developed APCVD reactor and the chemistry were optimized with respect to structural, electrical and optical properties of the films by adjusting the substrate temperature, gas flow rates and the amount of fluoride present in the vapor stream. Growth rates with respect to deposition time, substrate temperature and flow rates of precursors were found to be similar for both undoped (SnO 2 ) and doped (SnO 2 :F) samples. The SnO 2 :F films possess larger grains than the SnO 2 which may account for the lower resistivity and the higher mobility in the SnO 2 :F samples.