Retention loss in the ferroelectric (SrBi₂Ta₂O₉)-insulator (HfO₂)-silicon structure studied by piezoresponse force microscopy

¹ Institute of Modern Physics, Xiangtan University - Xiangtan 411105, Hunan, China
² Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University - Xiangtan 411105, Hunan, China
³ Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University Qingdao 266071, Shandong, China

^a xlzhong@xtu.edu.cn
^b jbwang@xtu.edu.cn

Received: 14 January 2012
Accepted: 27 March 2012

Abstract

Metal-ferroelectric-insulator-silicon (MFIS) structures with SrBi₂Ta₂O₉ as ferroelectric thin film and HfO₂ as insulating buffer layer were fabricated by pulsed-laser deposition. The interfaces and memory window of the MFIS structure were investigated. Piezoresponse force microscopy was used to observe the change of domain images in order to investigate the retention characteristics, which demonstrated that the MFIS structure experiences retention loss via a random-walk–type process, identified by a stretched exponential-decay model. The corresponding mechanism was discussed based on the time-dependent depolarization field.