Metal-ferroelectric-insulator-semiconductor (MFIS) capacitors and field effect transistors (FETs) with Al/BiFeO3/Y2O3/Si structure were fabricated. The capacitance-voltage (C-V) characteristics exhibit clockwise hysteresis loop due to the ferroelectric polarization of BiFeO3. The maximum C-V memory window was 0.88 V at a sweep voltage range of 5 V. Low leakage current density of 7×10-9 A/cm2 was measured at an applied voltage of 5 V using MFIS capacitors. The IDS-VDS and IDS-VGS characteristics of MFISFETs were measured. The subthreshold slope was 170 mV/dec and the maximum electron mobility was 155 cm2/V s.