Interface control of Bi4Ti3O12 film growth on Si(100) by use of an ultrathin silicon oxynitride buffer layer

Electrical properties of Bi4Ti3O12 (BiT) films on Si(100) were improved due to insertion of silicon oxynitride (SiON) buffer layers with thicknesses o f 1-2 nm. Capacitance-voltage measurements indicated that the improvement w as largely attributable to better Si interface properties rather than to th e difference of the BiT film quality. By means of x-ray photoelectron spect roscopy and high-resolution transmission microscopy, the Si interfaces of t he specimens with and without the SiON buffer layers were investigated. Con sequently, we found that a postannealing treatment at 680 degreesC inevitab ly resulted in nonuniform growth of Si oxide layers at the Si interface of the specimen without the SiON buffer layer, and that the layer thickness mo unted to approximately 10 rim. In contrast, 1-2-nm-thick. SiON buffer layer s terminated the growth of the additional oxide layer of less than about 3 nm, and the resulting Si oxide layers were quite uniform. (C) 2001 American Institute of Physics.