IMPROVEMENT OF RETENTIVITY IN TiO x/ HfO x BILAYER STRUCTURE FOR LOW POWER RESISTIVE SWITCHING MEMORY APPLICATIONS

This paper reports the bipolar resistive switching (BRS) characteristics in Al / Ti / TiO x/ HfO x/ Pt heterostructure during a DC sweep cycle with current compliance (CC) of 250 μA. The improvement in the switching performance in a CMOS compatible Al / Ti / TiO x/ HfO x/ Pt memory cell has been observed. The improvement is due to oxygen-rich HfO x 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 105 cycles, and good data retention of > 104 s at 85°C.