標題: | Design Space Analysis for Cross-Point 1S1MTJ MRAM: Selector-MTJ Cooptimization |
作者: | Chiang, Hung-Li Chen, Tzu-Chiang Song, Ming-Yuan Chen, Yu-Sheng Chiu, Jung-Piao Chiang, Katherine Manfrini, Mauricio Cai, Jin Gallagher, William J. Wang, Tahui Diaz, Carlos H. Wong, H. -S. Philip 電子工程學系及電子研究所 Department of Electronics Engineering and Institute of Electronics |
關鍵字: | Monte Carlo analysis;MTJ;read margin (RM);selector;spin-transfer torque-magnetoresistive random access memory (STT-MRAM);tunnel magnetoresistance ratio (TMR);variation |
公開日期: | 1-八月-2020 |
摘要: | To increase the density of magnetoresistive random accessmemory (MRAM) beyond the 1T1MTJMRAM cell in use today, the design space for 1S1MTJ MRAM array is analyzed by cooptimizing both selectors and MTJs. Current low-resistance MTJs for 1T1MTJ MRAM are not suitable for 1S1MTJ MRAM. Threshold-type selectors would induce a strong read disturb on the MTJ due to the snapback voltage (V-TH-V-HOLD) when the selector is turned on. Also, exponential-type selectorswould degrade the read margin (RM) due to its large ON-state resistance. When using existing selectors to achieve a 1-M-bit 1S1MTJ array, it is necessary to adjust the product of resistance and area (RA) and the diameter of the MTJ. An MTJ with the RA = 15 Omega . mu m(2) and the diameter = 50 nm can meet the criterion of RM > 10% for both exponential-type selectors (exponential slope = 300-500 mV/decade with the current density similar to 1 MA/cm(2)) and threshold-type selectors (V-TH-V-HOLD similar to 250 mV). A design space accommodating a selector variation of around 1% can be found for MTJs with tunnel magnetoresistance ratio (TMR) < 250%. With an increased TMR of 250%-350% of the MTJ, the tolerance of variations for exponential-type selectors and threshold-type selectors can be improved to 2% and 4%, respectively. This provides a chance for the 1S1MTJ MRAM with existing selectors. |
URI: | http://dx.doi.org/10.1109/TED.2020.3005118 http://hdl.handle.net/11536/155192 |
ISSN: | 0018-9383 |
DOI: | 10.1109/TED.2020.3005118 |
期刊: | IEEE TRANSACTIONS ON ELECTRON DEVICES |
Volume: | 67 |
Issue: | 8 |
起始頁: | 3102 |
結束頁: | 3108 |
顯示於類別: | 期刊論文 |