Patent ID: 6268624
Filing Date: 2001-07-31
Classification: H01L

Abstract:
A gate stack semiconductor device, comprising:at least one transistor gate;a semiconductor substrate;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;a source region and a drain region in the substrate below the at least one gate;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 .ANG. to 200 .ANG.,said at least one inner barrier film comprising at least one material selected from a group consisting essentially of: stoichiometric silicon nitride (Si.sub.3 N.sub.4), silicon dioxide (SiO.sub.2), and silicon oxynitride (SiON); andan outer barrier film covering said at least one inner barrier film, said outer barrier film having a uniform thickness in a range of 20 .ANG. to 200 .ANG., said outer barrier film comprising silicon-rich silicon nitride (Si.sub.3+n N.sub.4),said at least one inner barrier film and said outer barrier film, together, preventing formation of ""bird's beak"" structures during subsequent oxidation steps.