氧化铪基铁电薄膜材料及其存储单元性能研究

Due to its properties such as high speed, low consumption, excellent radiant resistance and long endurance, ferroelectric random access memory (FeRAM) shows a widespread application perspective in aerospace and consumer electronics fields. Hafnium oxide-based ferroelectric material is a newly developed FeRAM material alternative and becomes a hot research point immediately in these years. It is a promising material to solve the standard Complementary Metal Oxide Semiconductor (CMOS) process compatibility in conventional FeRAM manufacture with perovskite films. In this research project, we will launch the research from the crystal structure, electrode interface effect and characteristics optimization method to the performance of the storage unit. We aim to reveal the varied regularity of the crystal structure by doping, master the hafnium oxide-based ferroelectric thin film preparation method and acquire a high qualitative and CMOS process compatible hafnium oxide-based ferroelectric thin film. Through the device processing exploitation and capacitance model building, we try to solve the bit line capacitance matching problem and make ferroelectric memory cells. The research results of this project will provide scientific guidance and experimental basis for the hafnium oxide-based ferroelectric films’ application in FeRAM.

非挥发性铁电存储器具有高速度、低功耗、高抗辐射性能、长寿命的优异性能，在航空航天和民用电子领域具有广阔的应用前景。氧化铪基铁电材料是近年来备受瞩目的铁电存储器用材料，有望解决传统钙钛矿型铁电薄膜与CMOS工艺兼容性差的问题，有效提高铁电存储器密度，是当前学术界和产业界的一个研究热点。本申请项目拟从氧化铪基铁电材料的晶体结构、材料制备、电极界面效应与性能优化方法、存储单元器件性能等方面展开研究，揭示掺杂引入的氧化铪晶体演变规律，掌握氧化哈基铁电薄膜的制备方法和性能调控方法，制备出标准CMOS工艺兼容的高性能的铁电薄膜；通过基础工艺开发以及存储单元电路仿真，尝试解决位线电容匹配问题，研制铁电存储器存储单元。本项目研究结果将为氧化铪基铁电薄膜在存储器中的应用提供科学指导和实验依据。

铁电存储器是极具潜力的新型存储技术之一，然而传统的钙钛矿铁电材料的局限性如厚度要求、高污染和集成温度等一直限制了该领域的发展。氧化铪基铁电薄膜是一种与CMOS工艺完全兼容的新型铁电材料，有望突破铁电存储器发展缓慢的局面。本项目以新型氧化铪基铁电薄膜为基础，开展了从材料到器件的系列工作，（1）研究了氧空位对氧化铪铁电相稳定的影响，结果表明氧空位能在一定程度上减小铁电相与稳定相间能量差，从而起到稳定铁电相的作用。（2）采用射频反应磁控溅射和原子层沉积两种方法制备出了剩余极化可达16 μC/cm2，保持性能达（1e4 s），翻转次数达（1e7次）和抗总剂量电离辐射达5 Mrad(si)的HZO薄膜，（3）设计并并制备出了MFIS铁电栅结构的铁电晶体管，存储窗口不小于0.8 V（室温至85℃）。本项目研究成果能为铁电存储器的国产化提供重要的有益参考。