Growth and characterization of Pr_0.7Ca_0.3MnO ₃ thin films for resistance random access memory

We studied the appropriate growing conditions for Pr_0.7Ca _0.3MnO₃ (PCMO) thin films that can show good resistive switching characteristics for resistance random access memory (ReRAM) applications. The PCMO thin films were deposited on Pt/Ti/SiO ₂/Si(100) substrates at various substrate temperatures ranging from 500 to 700 °C and at various oxygen pressure from 100 to 300 mTorr by pulsed laser deposition. The PCMO thin films were found to be crystallized at substrate temperature above 600 °C and to exhibit columnar growth. The crystalline PCMO films showed hysteretic I-V characteristics in the Au/PCMO/Pt structure, meaning that resistive switching between high resistance state (HRS) and low resistance state (LRS) occurred. This resistive switching was caused by polarity change of bias voltage and found to be reversible. The resistance ratio of HRS and LRS increased with increasing substrate temperature. The resistive switching characteristics of the PCMO thin films were also dependent on the oxygen pressure during deposition. The higher the oxygen pressure the larger the resistance ratio of HRS and LRS. Consequently, the PCMO thin films grown at the substrate temperature of 700 °C under the oxygen pressure of 300 mTorr showed the largest resistance ratio of ∼14.5.