Study on resistance switching characteristics in SiON thin film for resistive random access memory
| Autor: | Lin, Yu-Shih, 林育仕 |
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| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 Recently, the conventional nonvolatile floating memory is expected to reach certain technical and physical limits in the future. In order to overcome this problem, alternative memory technologies have been extensively investigated, including ferroelectric random access memory (FeRAM), magneto resistive RAM (MRAM), phase-change RAM (PCRAM) and resistive RAM (RRAM).In all next generation nonvolatile memory, the resistive random access memories (RRAM) owing to the advantages of simple structure, lower consumption of energy, lower operating voltage, higher density, higher operating speed, higher endurance, higher storage time and non-destructive access which make it be the most popular candidate. In this thesis, we investigate and discuss the resistance switching current conduction mechanism for resistive random access memory of TiN/SiON/Cu/Pt structure RRAM device. The research can be split into four parts, the characteristic of RRAM devices with different top electrodes, the characteristics of ultra thin SiON film device, size effect and the device structure with copper layer at top and bottom electrode. At the part of the characteristic of RRAM devices with different top electrodes, we employed the Pt top electrode or Pt/Cu top electrode to figure out the physical resistance switching mechanism. The results showed that the copper atom will be introduced to SiON film when the device operate applied with bias voltage and formed Cu filament that can be served as a stretched electrode stretched electrode. Thus, a large electrical field can be generated at the tip of the electrode when applying bias on the device, resulting in better resistance switching characteristics. By fitting the current-voltage curve, we can extract the effective thickness of resistance switching layer which is very thin and at the interface between SiON and TiN electrode. Then, in order to verify the mechanism that we present, we fabricated a device with the ultra thin SiON film and Pt top electrode. The ultra thin SiON device present bipolar resistance switching characteristic, but the characteristic was more unstable than 38 nm SiON device with Pt/Cu top electrode. Because the ultra thin device was short of the tip electric field effect caused by Cu filament tip, the oxygen vacancies conduction path can be formed in anywhere of the SiON film and every circle of resistance switching may take place on different oxygen vacancies conduction path. At the part of size effect experiment, the resistance of high resistance state is dependent the area and the resistance of low resistance state is independent the area, this result conform to filament theory. Finial, we use the structure with copper layer as top and bottom electrode to confirm the correctness of mechanism of copper atom introduce to SiON. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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