PZT Ferroelectric Synapse TFT With Multi-Level of Conductance State for Neuromorphic Applications

Abstract

To fundamentally solve the bottleneck of Von Neumann's computing architecture, a neuromorphic thin-film transistor (NTFT) employing Pb(Zr, Ti)O3 (PZT) was investigated. The indium gallium zinc oxide (IGZO) channel back gate TFT structure was chosen to solve the diffusion of atoms that form a channel layer during the annealing process for crystallization of PZT. A post-deposition process with IGZO after annealing PZT and using an oxide-based material as a channel structure can minimize the diffusion phenomenon of junction materials and oxygen together, which leads to a high and reliable performance of the NTFT. The basic operations of synapses short-term memory (STM) and long-term memory (LTM) were also analyzed to confirm the application of a neuromorphic device. The high dielectric constant and polarization properties of Pb(Zr, Ti)O3 (PZT) allow the power consumption of spike signals used in spike dependent plasticity change to be reduced to 10 pJ. Moreover, a wide dynamic range of Gmax / Gmin ≅ 1000 was obtained, and the channel conductance was maintained over 40000 seconds. The optimized pulse achieved multi-level states (>32), which made the learning process efficient. This study verified that the PZT-TFT structure has a high potential and merits for neuromorphic devices.

Ferroelectric Controlled Interfacial Effect on the Electronic Properties of PZT Gated IGZO Channel Thin-Film Transistors

“…High-quality PZT thin films were obtained through annealing, leading to gate dielectrics with enhanced control capabilities, laying the foundation for the excellent characteristics of our transistors. IGZO films are highly desirable for the fabrication of TFT due to their excellent properties, such as high transconductance and impressive mobility. − Building upon the successful production of high-performance PZT thin films, we proceeded to deposit IGZO films with a thickness of approximately 10 nm onto the PZT ferroelectric thin films by using the PLD technique at room temperature. These IGZO films were utilized as the channel layer in the device architecture, as depicted in the inset of Figure a.…”

“…In recent research on PZT gated IGZO channel (PZT/IGZO) transistors, the effects of annealing on transport characteristics have been investigated, shedding light on the impact of this process on device performance . Similarly, Kim et al have delved into the enhancements of ferroelectric film properties, providing insights into the transistor’s on/off ratio . In addition, the structure of PZT/IGZO transistors has been studied to offer a perspective on improving transistor performance .…”

“…25 Similarly, Kim et al have delved into the enhancements of ferroelectric film properties, providing insights into the transistor's on/off ratio. 26 In addition, the structure of PZT/IGZO transistors has been studied to offer a perspective on improving transistor performance. 27 It is worth noting that the current understanding of defect characteristics in the PZT/IGZO interface layer and their influence on device performance remains limited.…”

Low-Thermal-Budget Ferroelectric Field-Effect Transistors Based on CuInP2S6 and InZnO

“…At a drain voltage ( V D ) of 0.1 V, the CIPS/IZO FeFET exhibits an on-state drain current ( I ON ) of 0.51 μA/μm and an off-state drain current ( I OFF ) of 3.3 × 10 –8 μA/μm. The on-state drain current was extracted at a V BG of 1 V, while the average off-state drain current was calculated as the average drain current within the gate voltage range of −7 to −6 V. Notably, the off-state current of the IZO-based transistor is significantly lower (10–100 times) than that of ferroelectric transistors based on 2D transition-metal dichalcogenide (TMDC), silicon, or other metal-oxide semiconductors. ,− The gate leakage at a V BG of 3 V is less than 10 –6 μA/μm. Our FeFET shows a sizable I ON / I OFF current ratio of 1.5 × 10 7 under V D = 0.1 V. The field-effect mobility is extracted using the equation μ = (d I DS /d V GS ) × [ L /( WC i V DS )], where L is the channel length, W is the channel width, and C i is the oxide capacitance.…”

Recent Advances and Future Prospects for Memristive Materials, Devices, and Systems

“…Various types of materials such as perovskites, 2D materials, polymers, and fluorite oxides have been found to have ferroelectricity and studied for next-generation memory devices. − The memory effect of the ferroelectric materials is attributed to the switching of electric dipole alignments between an upward and downward direction, driven by electric field. Ferroelectric memories include ferroelectric random-access memory (FeRAM), ferroelectric tunnel junction (FTJ), and ferroelectric transistors.…”