Effect of annealing temperature on electrical properties of metal–ferroelectric (BiFeO3)–insulator (Bi2Ti2O7)–silicon capacitors

Metal–ferroelectric–insulator–semiconductor (MFIS) capacitors with BiFeO3 (BFO) ferroelectric film and high-k Bi2Ti2O7 (BTO) buffer layer were fabricated. The effect of annealing temperature, especially on electrical properties of MFIS has been investigated. X-ray patterns show that the crystallinity of BFO is improved as the annealing temperature increases from 500 to 580 °C. However, a high temperature of 620 °C results in the problem of ions interdiffusion, which can be confirmed by the FeSEM image. The memory property is first enhanced and then deteriorated with the annealing temperature increasing. For BFO annealed at 580 °C, the MFIS structure shows the best capacitance–voltage (C–V) characteristic due to the increased ferroelectric polarization of BFO film and the reduced leakage current. The C–V hysteresis loop increases symmetrically around the zero-bias axis within ±2–±4 V and the maximum memory window of ∼2 V is obtained under ±5 V sweeping voltage. The 580 °C-annealed sample also shows a small relatively dielectric constant of 100 and low dissipation factor of 0.04 at the frequency of 100 kHz.

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► BiFeO3/Bi2Ti2O7/Si prepared by metal organic decomposition.
► High temperature results in ions interdiffusion.
► The maximum memory window of ∼2 V is obtained at ±5 V.
► The dielectric constant of 100 and dissipation factor of 0.04 are obtained at 100 kHz.