Abstract:
Each memory cell is a memory transistor which is provided on a top side of a semiconductor body and has a gate electrode which is arranged in a trench located between a source region and a drain region that are formed in the semiconductor material. The gate electrode is separated from the semiconductor material by a dielectric material. At least between the source region and the gate electrode and between the drain region and the gate electrode, there is an oxide-nitride-oxide layer sequence. The layer sequence is provided for the purpose of trapping charge carriers at the source and the drain.
Abstract:
An electrically conductive layer or layer sequence preferably includes a metal-containing layer applied to a metal silicide or a polysilicon layer to reduce the resistance of buried bit lines. The layer or layer sequence has been patterned in strip form so as to correspond to the bit lines and is arranged on the source/drain regions of memory transistors having an ONO memory layer sequence and gate electrodes that are arranged in trenches. The metal silicide is preferably cobalt silicide, and the metal-containing layer is preferably tungsten silicide or WN/W. .