| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a magnetic tunnel junction element having a large MR ratio suitable for MRAM. <P>SOLUTION: After a pinning layer 47, a pinned layer 48, and a tunnel barrier layer 49 are sequentially formed on a substrate 45, a free layer 50 composed of a first and a second NiFe layers 50a, 50b whose magnetostriction constants are opposite in sign is formed thereon. A first cap layer 51 made from NiFeHf and a second cap layer 52 made from Ta/Ru are sequentially formed on the free layer 50. Since the first cap layer 51 made from NiFeHf absorbs oxygen which has been captured in the free layer 50, the interface between the tunnel barrier layer 49 and the free layer 50 is sharpened, thereby substantially improving dR/R performance of the MTJ element. Since the first and second NiFe layers 50a, 50b have magnetostriction constants which are opposite in sign, net magnetostriction constant of the free layer 50 is extremely reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT |
