Tin Oxide Films Deposited By Ozone Assisted Thermal CVD

Abstract

I . lntroductilon Transparent conductive oxide(TC0) films have been widely employed as an optical transparent electrode in display devices and photovoltaic cells.[l,2] The development trends for TCO can be summarized into high conductivity, high transmittance, and chemical stability. From a view point of these requirements, TO(Sn02) has many possibilities. TO is an electrical conductor that has high conductivity with good transparency in the visible spectral range and excellent reflectivity in the infrared range. Also TO has the highest chemical stability. It is well known that the high conductivity of Sn02 is caused by both intrinsic defect(oxygen vacancy) and dopant(F, Sb, etc). [3,4,5] Therefore the unique method to obtain high quality transparent conductor is to cause electron degeneracy by introducing non-stoichiometry and appropriate dopants. Tin oxide has been produced by a number of techniques such as spray pyrolysis, DC(or rf)-sputtering, chemical vapor deposition(CVD), etc.[6,7,8,9] Among these techniques, organometallic CVD technique offers several advantages such as good control of film properties and relatively high growth rate on the order of 1 10 nmlsec.(lO] Tetramethyltin(TMT; (CH&Sn) is one of the volatile organotin sources and has good stability in air and moisture. [ I I ] In this study, the effects of deposition temperature and oxygen vacancies on the conductivity and optical properties of the films using oxygen containing ozone instead of pure oxygen have been investigated.