Title :
A study for 0.18 μm high-density MRAM
Author :
Motoyoshi, M. ; Yamamura, I. ; Ohtsuka, W. ; Shouji, M. ; Yamagishi, H. ; Nakamura, M. ; Yamada, H. ; Tai, K. ; Kikutani, T. ; Sagara, T. ; Moriyama, Koichi ; Mori, H. ; Fukamoto, C. ; Watanabe, M. ; Hachino, H. ; Kano, H. ; Bessho, K. ; Narisawa, H. ; Ho
Author_Institution :
Technol. Dev. Group, Sony Corp., Kanagawa, Japan
Abstract :
In this paper, we study to reduce the switching dispersion and improve 0/1 separation of Magnetic Tunnel Junction (MTJ) elements in order to realize high density MRAM. Various kinds of MTJ sizes and shapes have been evaluated and conclude that in ellipse like shape pattern aspect ratio more than 2 is enough for reproducing and reliable switching characteristics. As regards the reading characteristics, the combination of the optimized MTJ pattern and process makes 21.4 sigma separation between high and low resistance states. In further study of the relation between MTJ shapes and switching distribution, we found a "Saturn" shaped MTJ has best switching behavior. Also the toggle mode MRAM is evaluated and its effectiveness for high speed programming is confirmed.
Keywords :
CMOS integrated circuits; magnetic tunnelling; random-access storage; 0.18 μm high-density MRAM; 0.18 micron; Magnetic Tunnel Junction; ellipse like shape pattern aspect ratio; switching dispersion; Paper technology; Shape; Testing;
Conference_Titel :
VLSI Technology, 2004. Digest of Technical Papers. 2004 Symposium on
Print_ISBN :
0-7803-8289-7
DOI :
10.1109/VLSIT.2004.1345370
