Direct Observation of Tunnelling through 100-nm-Wide All Metal Magnetic Junction into Si

Nanoscaled spin-dependent tunnelling lines were patterned on doped Si and studied for tunnelling from the SDT ferromagnetic layer through an insulating barrier into Si. The injection contacts have the form of long strips with width and separation, ranging from 100nm to 2μm, and are patterned using e-beam lithography. The measured I-V characteristics versus temperature (80 to 300K) on the 100nm scaled devices between the layered-magnetic metals and the semiconductor clearly showed ballistic tunnelling, with weak dependence on the temperature. This is qualitatively different, at elevated temperatures, from 2-μm-wide scaled-up spin-dependent tunnelling structures, where thermal-ionic emission was observed to dominate carrier transport.