Patent ID: 6337246
Filing Date: 2002-01-08
Classification: H01L

Abstract:
A method of making a gate stack semiconductor device, comprising:forming at least one transistor gate over a semiconductor substrate; forming at least one tunnel oxide layer disposed between the gate and the substrate, the at least one tunnel oxide layer defining at least one edge extending between the substrate and the at least one gate; forming a source region and a drain region in the substrate below the at least one gate; forming at least one inner barrier film covering at least the edge of the at least one tunnel oxide layer, said at least one inner barrier film having a uniform thickness in a range of 20 to 200 angstroms, said at least one inner barrier film comprising at least one material selected from a group consisting essentially of: stoichiometric silicon nitride (Si3 N4), silicon dioxide (SiO2), and silicon oxynitride (SiON); and forming an outer barrier film covering said at least one inner barrier film, said outer barrier film having a uniform thickness in a range of 20 to 200 angstroms, said outer barrier film comprising silicon-rich silicon nitride (Si3+nN4), said at least one inner barrier film and said outer barrier film, together, preventing formation of â€œbird's beakâ€  structures during subsequent oxidation steps.