Study on microscopic model of resistive switching in amorphous tantalum pentoxide from first-principle calculations

As one of the emerging memory device, Ta
₂
O
₅
based RRAM has shown various outstanding features, such as low power consumption, high reliability and excellent scalability. In Ta
₂
O
₅
RRAM, the formation and the migration of oxygen vacancies are crucial to the resistive switching characteristics, reliability and uniformity of the device. In this paper, we used the first-principle simulation to study the properties of oxygen vacancies including forming energy and migration barrier in amorphous tantalum pentoxide. The β-Ta
₂
O
₅
supercell was built and annealing algorithm was used for generating amorphous Ta
₂
O
₅
in Material Studio. The band structure and DOS of both materials were studied by Vienna Ab initio simulation program (VASP). We also calculated the formation energy and migration barrier of oxygen vacancies, and discussed the mechanism of conductive path formation in amorphous Ta
₂
O
₅
. Finally, we proposed a new microscopic model of resistive switching mechanism in amorphous Ta
₂
O
₅
RRAM device.