Electrodeless characterization of memorized states of MFIS structure by photoreflectance spectroscopy

SrBi2Ta2O9 (SBT)/SiO2/Si structures have been characterized by photoreflectance spectroscopy (PRS) without electrode formation. SBT film was deposited on SiO2/n-Si by the metal-organic decomposition (MOD) method and annealed in O-2 atmosphere at 600degreesC. The voltage was applied by attaching ITO transparent electrodes during PRS measurement. The PRS spectral intensity of SBT/SiO2/Si structure has hysteresis characteristics as well as a C-V curve. Additionally, the spectral intensity gradually decreases with time, in a similar way to reduction of the capacitance. These results mean that the spectral intensity indicates the ferroelectricity of SBT film in SBT/SiO2/Si structure, so that it is considered that characterization of MFIS structure without electrode can be measured by PRS.