  The Andreev reflection (AR) in 2D HgTe/CdTe quantum well-superconductor
hybrid systems is studied. A quantized AR with AR coefficient equal to one is
predicted, which is due to the multi-Andreev reflection near the interface of
the hybrid system. Importantly, this quantized AR is not only universal, i.e.,
independent of any system parameters and quality of the coupling of the hybrid
system, it is also robust against disorder as well. As a result of this quantum
Andreev effect, the conductance exhibits a quantized plateau when the external
bias is less the superconductor gap.
