  Complete suppression of the native n-type Schottky barrier is demonstrated in
Al/InGaAs(001) junctions grown by molecular-beam-epitaxy. This result was
achieved by the insertion of Si bilayers at the metal-semiconductor interface
allowing the realization of truly Ohmic non-alloyed contacts in low-doped and
low-In content InGaAs/Si/Al junctions. It is shown that this technique is
ideally suited for the fabrication of high-transparency
superconductor-semiconductor junctions. To this end magnetotransport
characterization of Al/Si/InGaAs low-n-doped single junctions below the Al
critical temperature is presented. Our measurements show Andreev-reflection
dominated transport corresponding to junction transparency close to the
theoretical limit due to Fermi-velocity mismatch
