Investigation of voltage polarity-dependent switching and carrier conduction mechanisms of lead-free STO-based resistive memory

Author : ChihChieh Hsu, Xiu-Ming Wen, Kai-Zer Xiao

Abstract : This study investigates the polarity-dependent switching and carrier conduction mechanisms of lead-free perovskite strontium titanate (STO) resistive memory in a Cu/STO/n+-Si structure. The amorphous STO thin f ilm, approximately 10 nm thick and deposited via RF sputtering, exhibits high thermal stability, high resistivity, and a high breakdown electric field. Research confirms that the device demonstrates stable bipolar resistive switching (RS) characteristics with a strong dependence on voltage polarity: the forming and set processes can only be triggered by a positive bias, which facilitates the migration of copper ions to form conductive f ilaments (ECM mechanism), while a negative bias is required for the reset operation to rupture these f ilaments. If the negative voltage exceeds -11 V, the device undergoes irreversible hard breakdown and permanently loses its insulating properties. Analysis of ln(I)-ln(V) curves reveals that the device follows the Ohmic conduction mechanism (J∝V) at low electric fields and is controlled by space-charge-limited conduction (SCLC, J∝V2) at high electric fields. Furthermore, the energy barrier at the n+-Si/STO interface effectively suppresses electron injection, reducing leakage current and enhancing data retention capability. This study highlights the potential of STO films for advanced memory-in-logic computing architectures that are high-speed, stable, and CMOS-compatible.

Keywords : Resistive Random-Access Memory, Sputtering, Perovskite Materials

Conference Name : International Conference on Solid State Physics and Electronic Devices (ICSPEED-26)

Conference Place : Athens, Greece

Conference Date : 21st Mar 2026