Hyung-Jin Bae

Improvement of CBRAM Resistance Window by Scaling Down Electrode Size in Pure-GeTe Film

TaN-pure-GeTe-Cu bipolar switching devices which can be adaptable to semiconductor processes were fabricated as a function of top-electrode sizes (0.2, 0.4, 10, and 50 mum). The on/off resistance change ratio increased highly with decreasing electrode size. In particular, the on/off resistance change ratio was about 103 when the electrode size was scaled down to 200 nm. We obtained the characteristics of conductive bridging memory cell using pure-GeTe film without any doping of Cu or Ag; we also determined the reason for the enhancement of the on/off resistance change ratio when scaling down the electrode size.

Multibit Operation of Cu/Cu-GeTe/W Resistive Memory Device Controlled by Pulse Voltage Magnitude and Width

We report the demonstration of multilevel operation using Cu/Cu-GeTe/W nonvolatile resistive memory devices for enhanced storage density. We incorporated Cu atoms into GeTe solid-electrolyte switching layers in Cu/Cu-GeTe/W nonvolatile resistive memory devices by applying a bias to the sample holder during a radio-frequency sputtering process. By analyzing the dependence of the device current (resistance) on both the pulse input voltage magnitude and width, we achieved four distinct resistance levels that correspond to the 2-bit operation of a single memory cell. Moreover, a model was suggested and discussed to account for the observed multibit operation.