Memory properties of GeZrO2 based trilayer structure

Abstract

The memory properties of a trilayer structure of ZrO2/Ge-ZrO2/ZrO2/Si-p were investigated. The trilayer was prepared by magnetron sputtering deposition followed by a rapid thermal annealing process for obtaining Ge nanocrystals embedded in ZrO2 matrix. The X-ray diffraction patterns obtained on annealed structures show that both trilayer structures are cristallized, with narrow diffraction peaks. Ge as a separated phase is not evidenced in the diffractograms, instead is possible that Ge atoms enters in ZrO2 lattice structure and form a compound of ZrO3GeO8 crystallized in the tetragonal phase. In the case of ZrO2 control structure, the diffractograms show that the ZrO2 layer is crystallized in tetragonal phase. The memory properties are evidenced by C-V characteristics with counterclockwise hysteresis loop and a memory window of ΔV= 1.1V for the structure annealed at 570 °C and ΔV= 0.8 V for the structure annealed at 650 °C. The influence of the interface SiO2 layer on the frequency dependence of capacitance was evidenced by C-f characteristics.