Junqing Fan

Switching kinetics of SiC resistive memory for harsh environments

Cu/a-SiC/Au resistive memory cells are measured using voltage pulses and exhibit the highest ROFF/RON ratio recorded for any resistive memory. The switching kinetics are investigated and fitted to a numerical model, using thermal conductivity and resistivity properties of the dielectric. The SET mechanism of the Cu/a-SiC/Au memory cells is found to be due to ionic motion without joule heating contributions, whereas the RESET mechanism is found to be due to thermally assisted ionic motion. The conductive filament diameter is extracted to be around 4nm. The high thermal conductivity and resistivity for the Cu/a-SiC/Au memory cells result in slow switching but with high thermal reliability and stability, showing potential for use in harsh environments. Radiation properties of SiC memory cells are investigated. No change was seen in DC sweep or pulsed switching nor in conductive mechanisms, up to 2Mrad(Si) using 60Co gamma irradiation.

Back-end-of-line a-SiOxCy:H dielectrics for resistive memory

Resistive switching of W/amorphous (a)-SiOxCy:H/Cu resistive memories incorporating solely native back-end-of-line (BEOL) materials were studied. A-SiC1.1:H, a-SiO0.9C0.7:H, and a-SiO1.5C0.2:H were exploited as switching layers for resistive memories which all show resistive-switching characteristics with ultrahigh ON/OFF ratios in the range of 106 to 1010. Ohmic conduction in the low resistance state is attributed to the formation of Cu conductive filament inside the a-SiOxCy:H switching layer. Rupture of the conductive filament leads to current conduction dominated by Schottky emission through a-SiOxCy:H Schottky contacts. Comparison of the switching characteristics suggests composition of the a-SiOxCy:H has influences on VFORM and VSET, and current conduction mechanisms. These results demonstrate the capability to achieve functional W/a-SiOxCy:H/Cu using entirely BEOL native materials for future embedded resistive memories.Resistive switching of W/amorphous (a)-SiOxCy:H/Cu resistive memories incorporating solely native back-end-of-line (BEOL) materials were studied. A-SiC1.1:H, a-SiO0.9C0.7:H, and a-SiO1.5C0.2:H were exploited as switching layers for resistive memories which all show resistive-switching characteristics with ultrahigh ON/OFF ratios in the range of 106 to 1010. Ohmic conduction in the low resistance state is attributed to the formation of Cu conductive filament inside the a-SiOxCy:H switching layer. Rupture of the conductive filament leads to current conduction dominated by Schottky emission through a-SiOxCy:H Schottky contacts. Comparison of the switching characteristics suggests composition of the a-SiOxCy:H has influences on VFORM and VSET, and current conduction mechanisms. These results demonstrate the capability to achieve functional W/a-SiOxCy:H/Cu using entirely BEOL native materials for future embedded resistive memories.

Dataset for Active Counter Electrode in a-SiC Electrochemical Metallization Memory

Dataset for figures in: Morgan, K. et al (2017). Active Counter Electrode in a-SiC Electrochemical Metallization Memory. Journal of Physics D: Applied Physics.Funded by EPSRC

Switching mechanisms of Cu/SiC resistive memories with W and Au counter electrodes

Resistive memory is an emerging non-volatile memory, with high density, low power and a simple structure [1]. The memories switch between high resistance state (HRS) and low resistance state (LRS). The physical mechanism is based upon a conductive filament forming and rupturing between two electrodes. In electrochemical metallization memory (ECM) this filament is made from cations, originating from an active electrode, e.g. Cu or Ag [2]. The counter electrode is normally an inert material such as Pt or W. Although much research has been conducted into resistive memory, the role of the filament reduction at the counter electrode in ECM memories is still not fully understood.

Dataset for Switching kinetics of SiC resistive memory for harsh environments

Dataset for figures in: Morgan, K. et al (2015). Switching kinetics of SiC resistive memory for harsh environments. AIP Advances.Funded by EPSRC