Effects of an ultrathin silicon oxynitride buffer layer on electrical properties of ferroelectric Bi4Ti3O12 thin films on p-Si(100) surfaces

Electrical properties of ferroelectric Bi4Ti3O12 (BiT) films on Si(100) usi ng a 1 nm thick silicon oxynitride (SiON) buffer were investigated. The cap acitance-voltage (C-V) characteristics of Au/BiT/SiON/Si(100) exhibited hys teresis loops with a memory window of 2 V due to the ferroelectricity, and did not show large carrier injections. The effects of the SiON buffer were demonstrated in current-voltage characteristics. In the reverse bias region , a leakage current density of the specimen without the SiON buffer was muc h larger than that of the specimen with the buffer. Apart from these electr ical measurements, anomalous features appeared in C-V characteristics of th e illuminated specimen, which were likely to be due to the ac response of t he optically generated electrons in some trap states at the interface. (C) 2001 American Institute of Physics.