Si-based magnetic tunnel transistor with single CoFe base layer.

Magnetic tunnel transistors were prepared on Si(100) substrates by magnetron sputter deposition. By means of spin filtering through a single Co₉₀Fe₁₀ base layer, magnetocurrent ratios of 53%–55% and high transfer ratios of (1–2)×10^-4 for emitter-base bias of 1.5–2 V were obtained at 77 K. The bias dependence of the collector current showed the square-law behavior. From the modified Bell-Kaiser model, attenuation lengths of majority and minority spins of hot electrons are expected as 40±5 and 16±1 Å in the single Co₉₀Fe₁₀ layer, respectively. The decrease of transfer ratio was observed with decreasing base thickness from 80 to 30 Å, which may be related to the extension of the (Co₂Si and Fe) intermediate region formed at Co₉₀Fe₁₀/Si interface in the thinner base layer. [ABSTRACT FROM AUTHOR]