Effects of dopants on the electronic properties of Ba1-xSrxTiO3 thin films fabricated by MOSD technique

Ba1-xSrxTiO3 thin films are being developed for high density dynamic random access memory (DRAM) and low loss microwave devices. Properties of Ba1-xSrxTiO3 are typically varied by changing the Ba/Sr ratio and/or doping. In this paper, we report on the effects of acceptor and donor doping on the microstructural and electrical properties of Ba1-xSrxTiO3 thin films deposited by metalorganic solution deposition technique on platinum coated silicon substrates. Specifically, the electrical properties of both bulk and MOSD thin films of Ba0.6Sr0.4TiO3 doped with Mg [1], Al [2], La, and Ta have been investigated in detail. The electrical properties examined include the dielectric constants, loss tangents, leakage current, and tunability (% change in dielectric constant with an applied field). Also FT-Raman and FTIR spectroscopy has been performed on all specimens. Overall, it has been shown that it is possible to significantly improve the leakage current characteristics and control the tunability by doping the Ba1-xSrxTiO3 thin films.