Overview and high density application of HfOx based RRAM

A novel resistive memory with the TiN/Ti/HfO
x
/TiN stack is proposed and fully integrated with 0.18 µm CMOS technology. The excellent memory performances such as low operation current (down to 25 µA), low operation voltage (<1.5 V), high ON/OFF resistance ratio (above 100), and fast switching speed (10 ns) have been demonstrated for this ReRAM. Moreover, the device exhibits excellent scalability (scaling down to 50 nm), high switching endurance (>100 M cycles), and reliable data retention (10 years extrapolation at 220°C). A 1 Kb array with robust characteristics was also fabricated successfully. The endurance for all devices can exceed 10
⁶
cycles by a pulse width of 40 ns. New verification methods, which give tight distribution for high resistance (R
HIGH
) and low resistance (R
LOW
), are proposed to ensure a good operation window. Due to the high density application, the ultra-high LRS nonlinearity (>1000), robust retention, and good endurance are demonstrated in the HfO
X
based CRS device with a simple structure.