高Sc掺杂AlN薄膜铁电性能的研究

Study on the ferroelectric properties of high Sc doped AlN thin films

  • 摘要: 纤锌矿铁电材料因其大的剩余极化(Pr)、优良的高温稳定性以及与半导体工艺的良好兼容性, 受到了广泛的关注。然而, 纤锌矿钪掺杂氮化铝(AlScN)铁电薄膜应用于非易失性存储器的主要挑战是其较大的矫顽场(Ec), 以及在高电场下较大的漏电流。为制备具有低Ec和高电场下低漏电流的AlScN薄膜, 本文采用反应磁控溅射的方法, 在不同底电极(Mo、TiN和Al)上沉积了高钪含量的Al0.57Sc0.43N铁电薄膜。通过X射线光电子能谱、X射线衍射仪、原子力显微镜、扫描电镜和铁电测试仪对薄膜的成分、微观结构及电性能进了分析。实验结果表明: 在不同底电极上沉积的Al0.57Sc0.43N薄膜均表现出明显的c轴取向, 并展现出显著的铁电性, Ec-分别为2.6、3.5和2.3 MV/cm。TiN作为底电极时, AlScN铁电薄膜获得较大的剩余极化值且薄膜的漏电流较小。

     

    Abstract: Wurtzite ferroelectric materials have attracted extensive research interest due to their large remnant polarization, excellent high-temperature stability and compatibility with semiconductor processes.The main challenges hindering the application of Sc-doping AlN (AlScN) ferroelectric thin films in non-volatile memory is the large coercive field (Ec) and high leakage current at high electric field.In this study, high scandium content Al0.57Sc0.43N ferroelectric thin films were deposited using magnetron sputtering on different electrodes (Mo, TiN, and Al).The results show that Al0.57Sc0.43N thin films deposited on bottom electrodes (Mo, TiN, and Al) exhibit preferred c-axis orientation and obtained significant ferroelectricity, with coercive fields of 2.6, 3.5, and 2.3 MV/cm, respectively.However, the microstructure and breakdown strength are affected obviously by the electrodes.The Al0.57Sc0.43N thin film deposited on TiN bottom electrodes obtained a higher Pr value of 155 μC/cm2, and the leakage current is lower, making it a promising material for non-volatile ferroelectric memory applications.

     

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