As the semiconductor industry grapples with escalating scaling challenges associated with the floating gate MOSFET, alternative memory technologies like Resistive Random Access Memory (ReRAM) are gaining prominence in the scientific community. Boasting a straightforward device structure, ease of fabrication, and compatibility with CMOS (Complementary Metal-oxide Semiconductor) Back-end of Line (BEOL), ReRAM stands as a leading candi- date for the next generation of non-volatile memory (NVM).
ReRAM devices feature nanoionics-based filamentary switching, outperforming flash memory in terms of power consumption, scalability, retention, ON/OFF ratio, and endurance.
Furthermore, integrating ReRAMs within the CMOS BEOL/low-k Cu interconnect system not only reduces latency between the connectivity constraints of logic and memory modules but also minimizes the chip footprint.
However, investigations have revealed a significant concern surrounding ReRAMs—specifically, their electro-thermal reliability. This research provides evidence highlighting the critical influence of material properties, deposition effects, and thermal transport on the device's performance and reliability. Various material systems have undergone in this work scrutiny to comprehend the impact of intrinsic material properties such as thermal conductivity, specific heat capacity, thermal diffusivity, and deposition effects like surface roughness on the electroforming voltages of ReRAM devices.
The reference device structure considered in this work is Cu/TaOx/Pt, which has been compared with alternative configurations involving metals like Ru and Co as potential substitutes for Pt. Additionally, a new vehicle has been introduced to quantify cell degradation resulting from thermal cross-talk in crossbar Resistive Random Access Memory (ReRAM) arrays.
Furthermore, a novel methodology has been presented to predict cell degradation due to remote heating, taking into account the cell's location, the material properties of the device, and geometry of its electrodes. The experimental results presented in this study showcase filament rupture caused by remote heating, along with spontaneous filament restoration ensuing from the subsequent cooling of the ReRAM cell. / Doctor of Philosophy / As the demand for compact, high-speed logic-memory modules continues to surge, the diminishing silicon real estate in our gadgets poses a challenge in extending Moore's law to meet the scaling needs of the semiconductor device industry. To tackle this challenge, emerging memory technologies like Resistive Random Access Memory (ReRAM) are positioned as promising successors to flash memory.
ReRAM devices offer distinct advantages over flash memory, showcasing superior power consumption, scalability, long retention, a high ON/OFF ratio, and good endurance. Their compatibility with current CMOS (Complementary Metal-oxide Semiconductor) technology facilitates seamless integration. However, a significant concern associated with ReRAMs is their electro-thermal reliability.
This research delves into how material properties comprising a ReRAM device and fabrication factors, such as the surface roughness of the material, can impact the electrical and thermal reliability of a ReRAM cell. In this context, a novel methodology has been introduced to predict cell degradation within ReRAM crossbar arrays induced by thermal cross-talk, considering material properties and the geometry of the device. The new methodology has been thoroughly verified on manufactured ReRAM arrays with various composite electrodes. The study also presents experimental results demonstrating the rupture of cell filaments due to remote heating, along with instances of spontaneous filament restoration due to subsequent cooling.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/117276 |
| Date | 21 December 2023 |
| Creators | Chakraborty, Amrita |
| Contributors | Electrical Engineering, Orlowski, Mariusz Kriysztof, De La Reelopez, Jaime, Asryan, Levon Volodya, Lu, Guo Quan, Jia, Xiaoting |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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