Fabrication of HfO₂ based MOS and RRAM devices: A study of thermal annealing effects on these devices

The Hafnium Oxide (HfO₂) thin films were deposited by using e-beam evaporation technique. Au/HfO₂/Si-structured Metal Oxide Semiconductor (MOS) capacitors have been fabricated to study the transport mechanisms in these devices. Au/HfO₂/Au/Si-structure based Resistive Random Access Memory (RRAM) devices were also fabricated to elucidate their switching characteristics. Some of these devices were subjected to thermal annealing at 300° C and 500° C in the N₂ environment. Current-Voltage (I-V) and Capacitance-Voltage (C-V) measurements were carried-out before and after annealing. We have observed a reduction in the leakage current after 300° C annealing. Similar effects were observed in the RRAM devices in the switching performance where the formation and set voltages increase with the annealing temperature. Hence, we present the effects of annealing temperature on the electrical parameters of MOS and switching performance of RRAM devices.