Giant tunnelling electroresistance in metal/ferroelectric/semiconductor tunnel junctions by engineering the Schottky barrier.
Giant tunnelling electroresistance in metal/ferroelectric/semiconductor tunnel junctions by engineering the Schottky barrier.
复制标题
通过设计肖特基势垒在金属/铁电/半导体隧道结中产生巨大的隧道电阻
DOI：
10.1038/ncomms15217
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发表时间：
2017-05-17
影响因子：
16.6
通讯作者：
Wu D
中科院分区：
文献类型：
--
作者：
Xi Z;Ruan J;Li C;Zheng C;Wen Z;Dai J;Li A;Wu D
近年来，铁电隧道结因其在非破坏性读出非易失性存储器中的潜在应用而受到广泛关注。在铁电隧道结中使用半导体电极可以有效地提高隧道电阻。在这里，我们通过改变BaTiO 3厚度和Nb掺杂浓度在Nb：SrTiO 3表面设计肖特基势垒，对Pt/BaTiO 3/Nb：SrTiO 3金属/铁电/半导体隧道结的电阻进行了系统的研究。在Nb浓度为0.1wt%，BaTiO_3阻挡层厚度为4个单元的器件中，最佳的开/关比可达6.0 × 106，与商用Flash存储器相当。有了这个最薄的钛酸钡屏障，这表明一个可以忽略不计的电阻的隧道电流，但仍然是铁电的，该设备被减少到一个极化调制的金属/半导体肖特基结，表现出更有效的控制隧道电阻，以产生观察到的巨电阻。这些结果可以促进高性能非易失性电阻存储器的设计。
Recently, ferroelectric tunnel junctions have attracted much attention due to their potential applications in non-destructive readout non-volatile memories. Using a semiconductor electrode has been proven effective to enhance the tunnelling electroresistance in ferroelectric tunnel junctions. Here we report a systematic investigation on electroresistance of Pt/BaTiO3/Nb:SrTiO3metal/ferroelectric/semiconductor tunnel junctions by engineering the Schottky barrier on Nb:SrTiO3surface via varying BaTiO3thickness and Nb doping concentration. The optimum ON/OFF ratio as great as 6.0 × 106, comparable to that of commercial Flash memories, is achieved in a device with 0.1 wt% Nb concentration and a 4-unit-cell-thick BaTiO3barrier. With this thinnest BaTiO3barrier, which shows a negligible resistance to the tunnelling current but is still ferroelectric, the device is reduced to a polarization-modulated metal/semiconductor Schottky junction that exhibits a more efficient control on the tunnelling resistance to produce the giant electroresistance observed. These results may facilitate the design of high performance non-volatile resistive memories.