Study of the functional properties of ITO grown by metalorganic chemical vapor deposition from different indium and tin precursors

Functional properties of tin doped indium oxide (ITO) layers grown by MOCVD from different indium and tin precursors are investigated. Selected indium precursors are In(acac)3, In(tmhd)3 and InMe2OtBu, and tin precursors are DBTDA and Sn(acac)2. ITO layers are optically and electrically characterized to determine the better doping conditions. Differences in electrical properties of ITO layers are found when using InMe2OtBu, as compared to In(acac)3 and to In(tmhd)3. The best films present a resistivity of 2.5 × 10−4 Ω cm and a transmittance higher than 84% for high deposition temperatures (T ⩾ 600 °C). The nature of tin precursors modifies the optimal doping at which these characteristics are achieved. When doped by DBTDA optimal doping is 8 at.%, therefore close to the solubility limit of tin in In2O3 matrix; but when using Sn(acac)2, or In(acac)3/DBTDA combination, best functional characteristics are obtained for the maximal doping content obtained, i.e. 2.5 at.%. For optimized conditions, the resistivity decreases when deposition temperature increases except when using the couple InMe2OtBu/DBTDA without oxygen addition during deposition. For this combination of precursors a resistivity of 1 × 10−3 Ω cm is obtained at a deposition temperature of 350 °C and remains constant up to 600 °C. Only the films obtained from InMe2OtBu/DBTDA are crystalline state at a deposition temperature of 350 °C.