A semiconductor memory device having a capacitor is disclosed. The capacitor
includes
a bottom capacitor surface formed of a silicon-germanium single crystalline layer
or a dual layer in which a silicon-germanium single crystalline layer covers a
silicon single crystalline layer. The bottom capacitor surface is uneven and is
conventionally formed by an epitaxial method. The silicon germanium single crystalline
layer is approximately 5 to 50 percent germanium content by weight. The method
of fabricating the semiconductor memory device comprises: selectively exposing
the surface of a single crystalline silicon substrate at the region where the capacitor
bottom electrode is formed; supplying a source gas to grow a silicon germanium
single crystalline layer at the surface of the selectively exposed silicon substrate;
stacking a dielectric layer over the silicon germanium single crystalline layer;
and stacking a conductive layer over the dielectric layer to form a capacitor top
electrode. After forming the silicon germanium single crystalline layer to a predefined
thickness, a silicon single crystalline layer can be further grown at the silicon
germanium single crystalline layer. After forming the silicon germanium single
crystalline layer and before forming the dielectric layer, annealing can be performed
for a predefined time.
