GaN基半导体上BiFeO_3薄膜的生长与性能研究

Growth and Characterization of BiFeO_3 on GaN-Based Semiconductor

采用脉冲激光沉积法在(0001)取向的GaN以及AlGaN/GaN调制掺杂结构上制备了(111)取向的BiFeO3(BFO)薄膜。首先在导电氧化物SrRuO3和TiO2缓冲层包覆的GaN上制备了BFO薄膜,分析了在GaN上生长的BFO薄膜的面外取向、外延关系、表面形貌以及电学性能等性质。然后,在AlGaN/GaN调制掺杂结构上采用TiO2缓冲层生长了BFO薄膜,并采用光刻工艺分别在AlGaN表面制备Ti/Al/Ti/Au欧姆电极和BFO表面制备Ni/Au肖特基电极以形成二极管结构。C-V测试表明,由于BFO铁电薄膜极化的作用,BFO/TiO2/AlGaN/GaN结构具有1 V左右的逆时针窗口。

The（111） oriented BiFeO3 （BFO） films were grown by pulsed laser deposition on substrates of （0001）- GaN and the modulation doped A1GaN/GaN. The microstructures and ferroelectric property of the BFO were characterized with X-ray diffraction,piezo-response force microscopy and conventional probes. The impact of the TiO2 buffer layer, deposited on the modulation-doped AIGaN/GaN substrate, on growth of the BFO films was studied. A Ti/Al/Ti/Au Ohmic contact was fabricated on AlGaN surface and a Ni/Au Schottky contact was made on BFO surface by e-beam lithography, respectively. The capacity-voltage characteristics measured at a frequency of 1 MHz show that an anti-clockwise C- V window with a width of 1.0 V exists possibly because of the polarization of the BFO films.