Methods for making memory devices are disclosed for forming germanium nanocrystals in an oxynitride layer. The method includes: forming a first dielectric layer over a substrate; forming an oxynitride layer containing germanium nanocrystals over the first dielectric layer; forming a second dielectric layer over the oxynitride layer; forming a gate over the second dielectric layer; and providing source, drain, and channel regions in the substrate. In one example, the channel region is positioned to correspond to at least a portion of the gate.