以TiO_2为缓冲层在GaN上外延生长PZT铁电薄膜

Epitaxial Growth of Lead Zirconate Titanate Films on GaN Substrate with TiO_2 Buffer Layer

采用脉冲激光沉积技术在(0001)取向的GaN基片上以TiO2为缓冲层外延生长了PZT(111)单晶薄膜。X射线衍射分析表明PZT(111)衍射峰的摇摆曲线半高宽为0.4°,说明薄膜结晶性能良好。PZT薄膜疲劳特性测试结果表明,在经过107次翻转后PZT薄膜的剩余极化强度开始出现下降。P-E电滞回线和I-V测试表明PZT薄膜矫顽场(2Ec)为350 kV/cm,剩余极化(2Pr)约为96μC/cm2,在1 V电压下薄膜的漏电流密度为1.5×10-7A/cm2。以上性能测试结果表明,在半导体GaN上外延生长的PZT铁电薄膜性能基本满足铁电随机存储器的需要。

The（ 111 ）oriented lead zirconate titanate, PbZr0.52Ti0.48O3 （WZT）,films, were grown by pulsed laser deposition on substrates of GaN and TiO2-coated GaN, respectively. The microstructures and ferroelectric property of the PZT films were characterized with X-ray diffraction and conventional measurement. The influence of the film growth conditions, including deposition rate, annealing temperature and TiO2 buffer layer, on the epitaxial growth of the PZT films was stud- ied. The results show that the TiO2 buffer layer significantly improves the microstructures and ferroelectric property of the epitaxially grown PZT films. In addition, the PZT film material deposited on TiO2 coated GaN was found to be good enough to fabricate ferroelectric random access memory devices.