講演情報
[20p-A309-7]Epitaxial Growth of PZT Thin Films on HfO2-Buffered Si Substrates via Spin-coating Technique
〇(D)Haining Li1, Takeshi Kijima1,2, Risa Kataoka1, Hiroyasu Yamahara1, Hitoshi Tabata1, Munetoshi Seki1 (1.Univ. of Tokyo, 2.Gaianixx Inc.)
キーワード：
Ferroelectric、Buffer layer、Silicon-based
For large-scale commercial production, it is of great importance to transfer the superb single-crystalline features of perovskite oxides onto Si single-crystal wafers simply utilizing a straightforward fabrication method. Herein, the PbZr0.2Ti0.8O3 (PZT) thin film was prepared on the SrRuO3 (100)/Pt (200)/HfO2 (200)/Si (100) substrate by a spin-coating method and following rapid temperature annealing (RTA). The growth of SrRuO3, Pt, and HfO2 thin films has been reported in the previous research [2]. The XRD pattern of as-grown PZT film is shown in Fig. 1(a). The single-crystalline PZT film is highly oriented along the (100) direction, and its purity can result from the absence of extra crystalline impurity phases. Figure. 1(b) shows the reciprocal space mapping of the (–206) reflection of Si substrate and the (–204) reflection of the spin-coated PZT (100) and sputtered Pt (200) thin films, which suggests the epitaxial growth of the PZT films. The epitaxial growth of other layers (i.e. SrRuO3, Pt, and HfO2) can be confirmed in the previous report [2]. The figure also shows the in-plane epitaxial relationship PZT (100)//Pt (100)//Si (100). To characterize the room-temperature ferroelectricity of PZT film, standard polarization-voltage (P-V) loops were measured at 1 kHz with different maximum voltages, as shown in Fig. 1(c). The inset shows a schematic image of the device structure of Au/Cr/PZT/SRO/Pt/HfO2/Si used in the present study. The ferroelectric hysteresis loop appears at 10 V and becomes more pronounced with increasing voltages. The conventional hysteresis loops reflect a lack of contribution from leakage current, which achieves the saturated polarization Ps ≈ 50 μC/cm2 and remanent polarization Pr ≈ 42 μC/cm2 at 50 V. It is believed that utilizing the HfO2 buffer layer on a Si substrate will be a novel strategy for the simple and large-scale fabrication of single-crystalline perovskite oxides.