C–V studies on metal–ferroelectric bismuth vanadate (Bi2VO5.5)–semiconductor structure

Ferroelectric bismuth vanadate Bi2VO5.5 (BVO) thin films have been successfully grown on p-type Si(100) substrate by using chemical solution decomposition (CSD) technique followed by rapid thermal annealing (RTA). The crystalline nature of the films has been studied by X-ray diffraction (XRD). Atomic force microscopy (AFM) was used to study the microstructure of the films. The dielectric properties of the films were studied. The capacitance–voltage characteristics have been studied in metal–ferroelectric–insulator–semiconductor (MFIS) configuration. The dielectric constant of BVO thin films formed on Si(100) is about 146 measured at a frequency of 100 kHz at room temperature. The capacitance–voltage plot of a Bi2VO5.5 MFIS capacitor subjected to a dc polarizing voltages shows a memory window of 1.42 V during a sweep of ±5 V gate bias. The flatband voltage (Vf) shifts towards the positive direction rather than negative direction. This leads to the asymmetric behavior of the C–V curve and decrease in memory window. The oxide trap density at a ramp rate of 0.2 V/s was estimated to be as high as 1.45×1012 cm−2.