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

fYear

2004

Firstpage

22

Lastpage

23

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;

fLanguage

English

Publisher

ieee

Conference_Titel

VLSI Technology, 2004. Digest of Technical Papers. 2004 Symposium on

Print_ISBN

0-7803-8289-7

Type

conf

DOI

10.1109/VLSIT.2004.1345370

Filename

1345370