Spin injection/extraction into/from a n~+-Si channel using a Fe/Mg/Si3N4/Si(001) junction

摘要

Towards the realization of Si-based spintronic transport devices, we have studied spin injection/extraction into/from a n+-Si(001) substrate using Fe(3 nm)/Mg(tMg = 0?1 nm)/ SiOxNy(1 nm)/Si junctions (x : y = 4 : 6), and we have achieved a relatively high spin polarization of electrons PS = 16% and a relatively long spin lifetime ?S = 5.6 ns in the Si channel when tMg = 1 nm and the three-terminal measurement temperature TM was 4 K [1, 2]. This junction structure was found to be promising because of its fabrication method compatible with the Si complementary metal-oxide-semiconductor (CMOS) technology and its low junction resistance-area product RA ~700 ??m2. To deeply understand spin-related transport concerning spin injection/extraction through the Fe/Mg/SiOxNy junctions, further experiments with a different x/y ratio are very helpful. In this study, we prepare spintronic devices having a Fe(3 nm)/Mg(1 nm)/Si3N4/Si junction, and estimate PS and ?S using the three-terminal method. Our main finding is that the barrier material and its interface at the Si(001) surface have a crucial influence on PS and ?S, since these parameters are slightly decreased by changing from SiOxNy (x : y = 4 : 6) to Si3N4.