Semiconductor memory device having capacitor and method of forming the same

Abstract

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.