  We have measured the very low temperature (down to 30 mK) subgap resistance
of Titanium Nitride (Superconductor, Tc = 4.6 K)/highly doped Silicon
(Semiconductor) SIN junction (the insulating layer stands for the Schottky
barrier). As the temperature is lowered, the resistance increases as expected
in SIN junction. Around 300 mK, the resistance shows a maximum and decreases at
lower temperature. This observed behavior is due to coherent backscattering
towards the interface by disorder in Silicon ("Reflectionless tunneling"). This
effect is also observed in the voltage dependence of the resistance (Zero Bias
Anomaly) at low temperature (T<300 mK). The overall resistance behavior (in
both its temperature and voltage dependence) is compared to existing theories
and values for the depairing rate, the barrier resistance and the effective
carrier temperature are extracted.
