IMPROVEMENT OF RETENTIVITY IN TiOx/HfOx BILAYER STRUCTURE FOR LOW POWER RESISTIVE SWITCHING MEMORY APPLICATIONS

This paper reports the bipolar resistive switching (BRS) characteristics in Al/Ti/TiOx/HfOx/Pt heterostructure during a DC sweep cycle with current compliance (CC) of 250 mu A. The improvement in the switching performance in a CMOS compatible Al/Ti/TiOx/HfOx/Pt memory cell has been observed. The improvement is due to oxygen-rich HfOx layer insertion in simple metal-insulator-metal (MIM) sandwich structure. Analysis of current-voltage (I-V) characteristics revealed the trap-controlled space charge limited current (TC-SCLC) conduction mechanism is the most suitable mechanism signifying the dominant current conduction in all the bias regions and resistance states. Furthermore, this bilayer memory stack exhibits a tight distribution of switching parameters, good switching endurance up to 10(5) cycles, and good data retention of > 10(4) s at 85 degrees C.