金属/铁电体/半导体铁电隧道忆阻器的制备与性能研究

Most recently, memristors have attracted much attention due to the continuously tunable nonvolatile resistive state, which emulates biological synapses of brains. These make the memristor a promising candidate for future neuromorphic computational architectures.In this project, we propose a novel memristor scheme based on metal/ferroelectric/semiconductor tunneling heterostructures inspired by the ferroelectric field effect memories.The memristive properites can be realized in the proposed scheme by the bistably spontaneous polarization reversal, which give rise to the electrical modulation of barrier height and width simultaneously due to the ferroelectric field effect.Laser-MBE is employed in the present project to grow high quality ferroelectric/Nb:SrTiO3 epitaxial heterostructures. Memristive properties of the proposed ferroelectric tunneling structures are investigated by carefully controlling the applied pulse wave, which manipulates the switching behavior of polarization and hence modulates the barrier profile continuously. The origins of memristive behaviors are explored in terms of the ferroelectric field effect. The effect of microstructure parameters on the tunable capability and retention of resistive states are evaluated. These provide strongly experimental basis for application of the proposed ferroelectric tunnel memristors in neuromorphic microelectronic devices.

忆阻器具有电阻连续可调性和非易失性，能够对生物大脑神经突触的记忆、学习功能进行模拟，在神经态计算结构中具有潜在应用，因而受到研究人员的广泛关注。本项目拟借鉴铁电场效应存储器件的工作机制，以半导体为电极，提出基于金属/铁电体/半导体结构的铁电隧道忆阻器方案。利用自发极化双稳态和铁电场效应来同时调制结势垒的高度和宽度，在铁电隧穿结构中实现忆阻特性。本项目将采用激光分子束外延技术制备高质量铁电体/Nb:SrTiO3外延异质结构，通过控制输入的电脉冲波形来精确控制极化翻转行为，连续调制结势垒，对提出的铁电隧道忆阻结构进行研究，探索其忆阻特性来源，澄清铁电场效应在结势垒调制中的作用机制。考察若干微结构参数对该隧穿结构电阻连续可调性和阻态保持性的影响，为铁电隧道忆阻结构在神经态微电子器件上的应用打下基础。