Fabrication and characterization of nanoscale resistance change memory
Abstract/Contents
- Abstract
- As the current charge-based memory technologies such as DRAM and Flash Memory are facing their fundamental scaling limits, new types of memory technologies such as spin-torque-transfer RAM (STTRAM), phase-change memory (PCM), and metal-oxide resistance change memory (RRAM) have been actively explored. Among these candidates, RRAM devices utilize the resistance change property of the metal-oxide films, and have shown promising results such as fast switching speed, low programming current, and good CMOS compatibility. Despite the potential advantages, they suffer from the critical issues that must be addressed for the high-density memory application, which includes existence of forming-process, large variation in switching characteristics, and cell selection issue in cross-point structures. In this thesis, first, the process and characterization methodology for RRAM devices is demonstrated to verify the characteristics and potential issues in the nanoscale regime down to 50x50-nm^2 size. Unipolar switching memory cells using NiO thin films were fabricated by ebeam lithography process. The fabricated device characteristics and the scaling trends will be discussed. Next, two novel RRAM structures are proposed for improved cell characteristics. In the first structure, both top and bottom electrodes are processed prior to the metal-oxide deposition, and therefore, contamination-less programming region is achieved in the memory cell. Moreover, the novel structure features more confined conduction path compared to the conventional structure, which results in narrower low-resistance distribution. The process flow and characteristics of the nanoscale NiO memory cells using this structure will be demonstrated. In the second structure, an oxide-to-oxide interface is incorporated inside the memory cell in order to utilize the initial leakage and eliminate the high-voltage forming process (OTO Cell Technology). Due to this initial leakage, the as-fabricated AlOx memory cells exhibit low-resistance sates, while the conventional AlOx devices show high-resistance initial states. The new memory cell does not require the high-voltage forming process since the as-fabricated cells can be switched to high-resistance states with a regular RESET voltage. Finally, application of the forming-free OTO cells to the complementary resistive switch (CRS) scheme will be discussed using the measured cell characteristics. The CRS scheme was proposed as a potential solution to the high-density cross-point memory arrays for resistive memory. The novel memory cells with forming-free property demonstrate promising results, which enables the CRS scheme for bipolar switching RRAM cells.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Lee, Byoungil |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Wong, Hon-Sum Philip, 1959- |
| Thesis advisor | Wong, Hon-Sum Philip, 1959- |
| Thesis advisor | Nishi, Yoshio, 1940- |
| Thesis advisor | Saraswat, Krishna |
| Advisor | Nishi, Yoshio, 1940- |
| Advisor | Saraswat, Krishna |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Byoungil Lee. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Byoungil Lee
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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