  We have measured the conductance and shot-noise of superconductor-normal
metal (S-N) junctions between a Niobium (Nb) film and a 2-dimensional electron
gas (2DEG), formed in an InAs-based semiconductor heterostructure. Adjacent to
the junction, the 2DEG is shaped into a submicrometer beam-splitter. The
current shot-noise measured through one arm of the beam-splitter is found to be
enhanced due to Andreev reflection. Both noise and conductance measurements
indicate that the Nb-2DEG interface is of high quality with a transparency
approaching approx. 60-70 %. The present device can be seen as a
quasi-ballistic S-N beam-splitter junction.
