Im Solyee, Kang Seung-Youl, Kim Yeriaron, Kim Jeong Hun, Im Jong-Pil, Yoon Sung-Min, Moon Seung Eon, Woo Jiyong
ICT Creative Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea.
Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin, Gyeonggi 17104, Korea.
Micromachines (Basel). 2020 Sep 30;11(10):910. doi: 10.3390/mi11100910.
Since ferroelectricity has been observed in simple binary oxide material systems, it has attracted great interest in semiconductor research fields such as advanced logic transistors, non-volatile memories, and neuromorphic devices. The location in which the ferroelectric devices are implemented depends on the specific application, so the process constraints required for device fabrication may be different. In this study, we investigate the ferroelectric characteristics of Zr doped HfO layers treated at high temperatures. A single HfZrO layer deposited by sputtering exhibits polarization switching after annealing at a temperature of 850 °C. However, the achieved ferroelectric properties are vulnerable to voltage stress and higher annealing temperature, resulting in switching instability. Therefore, we introduce an ultrathin 1-nm-thick AlO layer at both interfaces of the HfZrO. The trilayer AlO/HfZrO/AlO structure allows switching parameters such as remnant and saturation polarizations to be immune to sweeping voltage and pulse cycling. Our results reveal that the trilayer not only makes the ferroelectric phase involved in the switching free from pinning, but also preserves the phase even at high annealing temperature. Simultaneously, the ferroelectric switching can be improved by preventing leakage charge.
由于在简单的二元氧化物材料体系中已观察到铁电性，它在先进逻辑晶体管、非易失性存储器和神经形态器件等半导体研究领域引起了极大的兴趣。铁电器件的实现位置取决于具体应用，因此器件制造所需的工艺约束可能不同。在本研究中，我们研究了高温处理的Zr掺杂HfO层的铁电特性。通过溅射沉积的单个HfZrO层在850℃退火后表现出极化切换。然而，所实现的铁电性能易受电压应力和更高退火温度的影响，导致切换不稳定。因此，我们在HfZrO的两个界面处引入了一个1nm厚的超薄AlO层。AlO/HfZrO/AlO三层结构使得诸如剩余极化和饱和极化等切换参数不受扫描电压和脉冲循环的影响。我们的结果表明，该三层结构不仅使参与切换的铁电相免于钉扎，而且即使在高退火温度下也能保持该相。同时，通过防止漏电荷可以改善铁电切换。
