Tunnel Contacts for Spin Injection into Silicon: The Si-Co Interface with and without a MgO Tunnel Barrier—A Study by High-Resolution Rutherford Backscattering
Figure 6
(a) HRBS spectra of a Si sample before and after MgO evaporation. Before evaporation: spectrum of the high-energy Si edge (solid circles) and RUMP simulation (solid line) of the clean Si. After MgO evaporation: spectrum of Si with Mg and O peaks of the 18.3 ML thick MgO film on top (open circles) and RUMP simulation (solid line) of the 18.3 ML thick MgO film as prepared on Si (100) surface. The spectrum shows that the MgO film is very uniform. Surplus oxygen at the surface of the MgO film is clearly visible. (b) HR-TEM cross-sectional micrograph of a Si (100)/MgO (18.3 ML)/Co structure. The lines have been added at the interfaces to aid the eye in distinguishing the layers of small contrast difference.
