氮气或氧气气氛退火的氧化铪材料电荷泄漏情况研究

本文中, 使用开尔文探针显微镜,研究了不同退火气氛(氧气或氮气)情况下氧化铪材料的电子和空穴的电荷保持特性。与氮气退火器件相比,氧气退火可以使保持性能变好。横向扩散和纵向泄露在电荷泄露机制中都起了重要的作用。 并且,保持性能的改善与陷阱能级深度有关。氮气和氧气退火情况下,氧化铪存储结构的的电子分别为0.44 eV, 0.49 eV,空穴能级分别为0.34 eV, 0.36 eV。 最后得到,不同退火气氛存储器件的电学性能也与KFM结果一致。对于氧化铪作为存储层的存储器件而言,对存储特性的定性和定量分析,陷阱能级,还有泄漏机制研究是十分有意义的。

Investigation of charge loss characteristics of HfO2 annealed in N2 or O2 ambient

The retention characteristics of electrons and holes in hafnium oxide with post-deposition annealing in a N₂ or O₂ ambient were investigated by Kelvin probe force microscopy. The KFM results show that compared with the N₂ PDA process, the O₂ PDA process can lead to a significant retention improvement. Vertical charge leakage and lateral charge spreading both played an important role in the charge loss mechanisms. The retention improvement is attributed to the deeper trap energy. For electrons, the trap energy of the HOS structure annealed in a N₂ or O₂ ambient were determined to be about 0.44 and 0.49 eV, respectively. For holes, these are about 0.34 and 0.36 eV, respectively. Finally, the electrical characteristics of the memory devices are demonstrated from the experiment, which agreed with our characterization results. The qualitative and quantitative determination of the charge retention properties, the possible charge decay mechanism and trap energy reported in this work can be very useful for the characterization of hafnium charge storage devices.