Reliability of Au/PZT/BIT/p-Si ferroelectric diode

Abstract

A ferroelectric memory diode that consisted of Au/PZT/BIT/p-Si multilayer configuration was fabricated by pulsed laser deposition (PLD) technique. The reliability issues (I–V characteristics, capacitance retention, fatigue and imprint) were investigated. The I–V curve showed the conventional Schottky diode characteristics with a small current density of −5.3×10−10 A/cm2 at a voltage of −4 V and 6.7×10−8 A/cm2 at a voltage of +4 V, and this characteristic can be maintained below 50°C. The capacitance variety of the ferroelectric diode was only 5% in 10 hours after withdrawing the applied bias of +5 V or −5 V, indicating the diode had good capacitance retention. By applying 100 kHz bipolar pulses of 5 V amplitude, the decay in remanent polarization was only 10% after 109 switching cycles, and meanwhile the increase in coercive field was 12%. After being irradiated for 20 min with a 200 W ultraviolet ray lamp, the remanent polarization and coercive field had both varied, and a voltage shift was observed, but the figure of merit FOM was about 0.2 and the diode had no imprint invalidation.