1,720,968 research outputs found
Electrical and material characterisation of silicon carbide based resistive memories
No full textResistive memory is widely considered as a promising non-volatile memory to address the demands for high-density data storage, low power consumption, augment the performance of current transistor-based memories or even replace current transistor-based memories. Main advantages of resistive memory include simple Metal/Insulator/Metal device structure, low switching voltage, fast switching speed, and long data retention. Material properties of the insulating layer play important roles in the overall performance of resistive memory. Among a range of insulator materials of resistive memories that have been reported in the literature thus far, Silicon Carbide (SiC) has shown great promise as the insulating layer which leads to resistive memories with desirable performance including large ON/OFF ratios, excellent data retention, and CMOS compatibility in device fabrication. However, there are still many challenges to be solved in the resistive memories using SiC, especially amorphous (a)-SiC as the insulating layer to be superior to other resistive memories. One of these challenges is to reduce the forming voltage which could affect the power consumption and complexity of the peripheral power-supply circuit. Another challenge is to achieving device structure exclusively using native CMOS back-end-of-line materials which would enable low fabrication cost and low development time to embed a-SiC based resistive memories in the CMOS back-end-of-line layer. Moreover, the existing Electrochemical metallisation (ECM) mechanism cannot precisely predict the switching voltage nor resistance state of resistive memories, and there is a lack of knowledge on how the material properties of the insulating layer affect resistive-switching performance and mechanisms. Further exploration of the resistiveswitching characteristics to improve the understanding of switching mechanism and influence of material and electrical properties of the insulating layer on resistive-switching characteristics are needed from a scientific point of view. This thesis focuses on addressing all the challenges above, highlights the influence of insulator material choice on the performance of resistive memories using SiC as the insulating layer. Amorphous silicon carbide (a-SiC), Cu embedded a-SiC (a-SiC:Cu), CMOS back-end-of-line dielectrics (a-Si(O)C:H), and crystalline SiC (c-SiC) are used as the insulating layer of resistive memories in this thesis. The material and electrical properties of these insulator materials are characterised. Metal/Insulator/Metal resistive memories using these insulator materials as the insulating layer are fabricated and the resistive-switching characteristics of these resistive memories are studied. Ultrahigh ON/OFF ratios up to 109 which enables fast and reliable detection of the states, are achieved. Forming voltage and SET voltage are reduced and endurance is improved by embedding Cu nanoparticles in the a-SiC insulating layer. Non-volatile resistive-switching is observed on resistive memories using exclusively native CMOS back-end-of-line materials including Cu, W, a-SiC:H, aSiOC:H, and a-SiCO:H. The influence of material and electrical properties of the insulating layer on resistive-switching characteristics of resistive memories made exclusively using CMOS back-end-ofline materials is discussed
Amorphous SiC resistive memory with embedded Cu nanoparticles
No full textAmorphous SiC with embedded Cu nanoparticles (a-SiC:Cu) was investigated as the insulator layer of Cu/a-SiC:Cu/Au resistive memory. The effect of the Cu embedding on resistive switching characteristics was studied for 20 and 30 vol% Cu. Reduced forming and SET voltages and increased endurance was observed for devices with 30Cu%. At the same time, all key advantageous characteristics of amorphous SiC resistive memory such as ON/OFF ratio of 107 and the co-existence of bipolar and unipolar modes were maintained upon Cu embedding. All above suggests that Cu embedding could be considered as a promising method to improve the overall performance of Cu/a-SiC:Cu/Au resistive memories
Dataset for Back-end-of-line a-SiOxCy:H dielectrics for resistive memory
No full textDataset of figures in the paper Fan, J., Kapur, O., Huang, R., De Groot, C., & Jiang, L. (2018). Back-end-of-line a-SiOxCy:H dielectrics for resistive memory. AIP Advances. This dataset including XPS on a-SiOxCy:H films and current-voltage measurements tests on W/a-SiOxCy:H/Cu resistive memories.</span
Dataset for Switching kinetics of SiC resistive memory for harsh environments
No full textDataset for figures in:
Morgan, K. et al (2015). Switching kinetics of SiC resistive memory for harsh environments. AIP Advances.
Funded by EPSRC</span
Switching kinetics of SiC resistive memory for harsh environments
No full textCu/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. All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License
Back-end-of-line a-SiOxCy:H dielectrics for resistive memory
No full textResistive 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 1E6 to 1E10. 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
Microstructure and electrical properties of co-sputtered Cu embedded amorphous SiC
No full textDataset of figures in the paper "Microstructure and electrical properties of co-sputtered Cu embedded amorphous SiC". These dataset including EDS, XRD, SEM, low-temperature resistance, resistivity measurements on a-SiC:Cu films and capcitance and current density-voltage measurements on Cu/a-SiC:Cu/Au microcapacitors.</span
Properties of SiC resistive memory for harsh environments
No full textAmorphous silicon carbide resistive memory cells are shown to exhibit the highest ROFF/RON ratio recorded for any resistive memory in pulsed switching. The switching characteristics are investigated and fitted to a numerical model. The SET mechanism for these cells is found to be due to ionic motion without joule heating contributions, leading to large VSET. The high thermal conductivity and resistivity of the SiC memory cells result in slow switching but, with high state and thermal stability, show potential for harsh environment use. Radiation properties of SiC memory cells are investigated. No change was seen in switching properties nor in conductive mechanism, up to 2Mrad(Si) using 60Co ionizing gamma radiation
- …
