Characterization of Au/Pb(Zr_0.96Ti_0.04)O₃/Al₂O₃/Si antiferroelectric field-effect transistors for memory application

Polarization-voltage (P-V) hysteresis loops and polarization retention were studied for Au/Pb(Zr_0.96Ti_0.04)O₃/Al₂O₃/Pt antiferroelectric capacitors with different Al₂O₃ layer thicknesses. The high-field ferroelectric phase after poling can be pertained to zero external field with the choice of an appropriate Al₂O₃ layer thickness. At the same time, a strong depolarization field across the Al₂O₃ layer is generated with the direction opposite to the field across the Pb(Zr_0.96Ti_0.04)O₃ layer. The depolarization-field direction can be reversed with the domain switching of the high-field ferroelectric phase, possessing the potential application of antiferroelectric memories. A large memory window of 10 V was observed for Au/Pb(Zr_0.96Ti_0.04)O₃ (50 nm)/Al₂O₃ (6.3 nm)/n-Si (100) field-effect transistors, as confirmed from the capacitance sweeping under voltages between −19 and +19 V. The high/low capacitance ratio is over 8:1, and the ratio remains stable with time over 4 h after programming voltage of ±19 V at 80°C, in suggestion of the excellent retention of the memory.