Investigation on polarization characteristics of ferroelectric memories with thermally stable hafnium aluminum oxides

Abstract

In this work, we successfully demonstrated the 9.6-nm-thick HfAlOx ferroelectric memory using light aluminium doping of 6.5% to form ferroelectric orthorhombic phase. Compared to ferroelectric HfZrOx film with zirconium diffusion issue, the HfAlOx film showed excellent thermal stability under high temperature annealing. Besides, the ferroelectric HfAlOx also exhibited robust polarization characteristics under endurance cycling test. A > 10(6) stressed cycles with 4 MV/cm can be measured and a long endurance was sustained over 5 x 10(7) cycles under 3.6 MV/cm. Therefore, the HfAlOx film showed the great promise for integrating in high performance ferroelectric memory with thermal budget concerns.