Infineon Technologies Ag

Stefan Rongen

Martin Schrems

Dietmar Temmler

Jörn Lützen

Rudolf Strasser

Wolfgang Gustin

Barbara Schmidt

Ulrike Gr&uuml;ning-Von Schwerin

Daniel Köhler

To fabricate a trench capacitor in a substrate, a trench is formed in the substrate. The trench has an upper region and a lower region. In the trench, first of all nanocrystallites and/or a seed layer for nanocrystallites are deposited in the upper region and the lower region. Then, the nanocrystallites and/or the seed layer are removed from the upper region of the trench by means of an etching process. The etching parameters of the etching process are selected in such a way that the seed layer and/or the nanocrystallites which are uncovered in the upper region and the lower region are removed only from the upper region. Consequently, an expensive mask layer can be avoided in the lower region of the trench.

Method of etching a layer in a trench and method of fabricating a trench capacitor

A trench capacitor is formed in a trench, which is disposed in a substrate. The trench is filled with a conductive trench filling which functions as an inner capacitor electrode. An epitaxial layer is grown on the sidewall of the trench on the substrate. A buried strap is disposed between the conductive trench filling with the second intermediate layer and the epitaxially grown layer. A dopant outdiffusion formed from the buried strap is disposed in the epitaxially grown layer. Through the epitaxially grown layer, the dopant outdiffusion is further removed from a selection transistor disposed beside the trench, as a result of which it is possible to avoid short-channel effects in the selection transistor.

Semiconductor memory cell and method for fabricating the memory cell

Growing community of inventors

Dresden, Germany

Stefan Rongen