  We investigate the effect of strain on the etching rate of two SiGe wet
etchants, namely NH4OH:H2O2 and H2O2. For both etchants, we found that there is
no appreciable strain selectivity, i.e. the etching rates do not depend on the
actual strain state in the SiGe films. Instead, for the NH4OH:H2O2 solution,
the rates are primarily determined by the Ge content. Finally, we show that
both etchants are isotropic with no preferential etching of particular facets.
