Tunneling electroresistance effect in a Pt/Hf_(0.5)Zr_(0.5)O_2/Pt structure

摘要

The present work reports the fabrication of a ferroelectric tunnel junction based on a CMOS compatible 2.8 nm-thick Hf_(0.5)Zr_(0.5)O_2 tunnel barrier. It presents a comprehensive study of the electronic properties of the Pt/Hf_(0.5)Zr_(0.5)O_2/Pt system by X-ray photoelectron and UV-Visible spectroscopies. Furthermore, two different scanning probe techniques (Piezoresponse Force Microscopy and conductive-AFM) were used to demonstrate the ferroelectric behavior of the ultra-thin Hf_(0.5)Zr_(0.5)O_2 layer as well as the typical current-voltage characteristic of a ferroelectric tunnel junction device. Finally, a direct tunneling model across symmetric barriers was used to correlate electronic and electric transport properties of the ferroelectric tunnel junction system, demonstrating a large tunnel electroresistance effect with a tunneling electroresistance effect ratio of 20.