Neuromorphic machines are intriguing for building energy-efficient intelligent systems, where spiking neurons are pivotal components. Recently, memristive neurons with promising bio-plausibility have been developed, but with limited reliability, bulky capacitors or additional reset circuits. Here, we propose an anti-ferroelectric field-effect transistor neuron based on the inherent polarization and depolarization of Hf0.2Zr0.8O2 anti-ferroelectric film to meet these challenges. The intrinsic accumulated polarization/spontaneous depolarization of Hf0.2Zr0.8O2 films implements the integration/leaky behavior of neurons, avoiding external capacitors and reset circuits. Moreover, the anti-ferroelectric neuron exhibits low energy consumption (37 fJ/spike), high endurance (>1012), high uniformity and high stability. We further construct a two-layer fully ferroelectric spiking neural networks that combines anti-ferroelectric neurons and ferroelectric synapses, achieving 96.8% recognition accuracy on the Modified National Institute of Standards and Technology dataset. This work opens the way to emulate neurons with anti-ferroelectric materials and provides a promising approach to building high-efficient neuromorphic hardware.

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The non-ideal characteristics at the interfaces of anti-ferroelectric (AFE) film and electrodes will greatly affect the potential performance in the way to embedded dynamic random-access memory applications. In this paper, we have proposed a high-performance AFE TiN/HfxZr1−xO2/TiN capacitor fabricated by fully atomic layer deposition grown and alcohol-thermal high-pressure annealing methods that have been employed to avoid exposure to the ambient atmosphere and cure the interface defects induced by the inevitable oxidization of electrodes. Due to the high improvement of the interface quality, the capacitors based on ultra-thin (∼6 nm) AFE film show competitive memory performances, such as low operating voltage (−0.6/1.8 V), high speed (10 ns), long retention time (103 s), and high endurance (1012). The final benchmark demonstrates that the proposed AFE TiN/HfxZr1−xO2/TiN capacitor is a promising candidate toward the next generation high-speed and high-density embedded memory.

The interface difference between HZO and the upper and lower electrodes induced by the sequence of the process flow could lead to the general asymmetry in the structure and performance of metal-ferroelectric-metal (MFM) capacitors, which may cause serious reliability problems. In this letter, we have exploited a special high pressure annealing (HPA) process, called alcohol-thermal method (ATM), to improve the symmetry of TiN/HZO/TiN capacitors. The original control device exhibits asymmetric leakage current and coercive fields. This has been significantly improved by the ATM, which was performed at temperature of 240 • C and atmospheric pressure of 70 atm, in C 2 H 6 O ambient. The enhancement of ferroelectricity can be attributed to the reduction of the thickness and defects of the non-ferroelectric layers in the device. The improvement of symmetry leads to the operation ability under low voltages, which is critical to the endurance of devices. Under the electric field of 2.4 MV/cm with 10 MHz frequency, the lifetime of the TiN/ HZO/TiN device after HPA process was measured up to 10 10 cycles. This work provides an effective way to improve symmetry and ferroelectricity of hafnium-based ferroelectric capacitors.INDEX TERMS Ferroelectric device, high pressure annealing, leakage current, endurance, Zr-doped HfO 2 (HZO).

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