State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu, P. R. China.
IEEE Trans Ultrason Ferroelectr Freq Control. 2010 Oct;57(10):2192-7. doi: 10.1109/TUFFC.2010.1677.
Typical perovskite oxides SrTiO₃ (STO) and PbZr₀.₅₂Ti₀.₄₈O₃ (PZT) were fabricated on GaN semiconductor substrates by pulsed laser deposition. STO and PZT films were deposited on bare GaN, TiO₂, and MgO-buffered GaN. The effects of TiO₂ and MgO buffer-layers on the orientations and electric properties of the perovskite films were systematically studied. The crystalline properties were in situ monitored by reflective high energy electron diffraction and ex situ characterized by X-ray diffraction. It was found that the epitaxial temperature of STO and PZT was reduced by inserting a buffer layer. (111)-oriented films were obtained on bare and TiO₂-buffered GaN. However, the orientations of the perovskite films were changed to be (110) when deposited on MgO buffer layer. Furthermore, PZT films deposited on MgO- and TiO₂-buffered GaN show better electric performance compared with these films directly deposited on GaN. These results show that perovskite oxide could be epitaxially grown on GaN semiconductor substrates by inserting a proper buffer layer.
采用脉冲激光沉积法在 GaN 半导体衬底上制备了典型的钙钛矿氧化物 SrTiO3（STO）和 PbZr0.52Ti0.48O3（PZT）。STO 和 PZT 薄膜沉积在裸 GaN、TiO2 和 MgO 缓冲 GaN 上。系统研究了 TiO2 和 MgO 缓冲层对钙钛矿薄膜取向和电性能的影响。通过反射高能电子衍射原位监测晶体性能，通过 X 射线衍射对其进行了非原位表征。结果表明，插入缓冲层降低了 STO 和 PZT 的外延温度。在裸 GaN 和 TiO2 缓冲 GaN 上获得了（111）取向的薄膜。然而，当沉积在 MgO 缓冲层上时，钙钛矿薄膜的取向变为（110）。此外，沉积在 MgO 和 TiO2 缓冲 GaN 上的 PZT 薄膜的电性能优于直接沉积在 GaN 上的薄膜。这些结果表明，通过插入适当的缓冲层，可以在 GaN 半导体衬底上外延生长钙钛矿氧化物。
