Title
A Smaller, Faster, and More Energy-Efficient Complementary STT-MRAM Cell Uses Three Transistors and a Ground Grid: More Is Actually Less.
Abstract
Spin-transfer torque magnetoresistance random access memory is a major contender for static random access memory replacement in embedded caches at advanced fin field effect transistor nodes. It suffers, however, from the low resistance difference between the bistable states of the magnetic tunnel junction (MTJ). Variability on MTJ resistance and access transistors makes reliable read-out even more challenging. This triggered the use of complementary cells for low level caches needing high performance. This paper, focusing on the lower level caches, shows an improved 3T 2MTJ cell with a ground grid and a novel three transistor read and write operation to improve area density, sense margin, write performance, and write energy consumption. Despite the cell’s three transistors, the improved array configuration reduces the cell area by 22% as compared with the 2T 2MTJ cell, making it only 55% larger than a 1T 1MTJ cell. The novel mismatch tolerant read operation uses all three transistors and increases the sense margin by up to 88%. The novel variation resilient write operation also uses all three transistors and takes advantage of the inherent MTJ characteristics and complementary operation of the cell. This increases the write performance by $2\\times $ and reduces the write energy by $3\\times $ compared with the 2T 2MTJ cell and by $1.5\\times $ compared with the 1T 1MTJ cell.
Year
DOI
Venue
2017
10.1109/TVLSI.2016.2633004
IEEE Trans. VLSI Syst.
Keywords
Field
DocType
Resistance,Transistors,Magnetic tunneling,Tunneling magnetoresistance,Switches,Energy consumption,Process control
Computer science,CPU cache,Static random-access memory,Electronic engineering,Magnetoresistive random-access memory,Non-volatile memory,Tunnel magnetoresistance,Transistor,Energy consumption,Electrical engineering,Random access
Journal
Volume
Issue
ISSN
25
4
1063-8210
Citations 
PageRank 
References 
1
0.39
4
Authors
6
Name
Order
Citations
PageRank
Raf Appeltans182.32
Praveen Raghavan230847.48
G. Kar396.91
Arnaud Furnemont422.76
Liesbet Perre5335.61
Wim Dehaene6874116.42