ELECTRICAL CHARACTERISTICS OF ULTRATHIN2.5NM GATE QUALITY LPCVD NITRIDE/OXIDE FILMS

摘要

Low pressure chemical vapor deposited nitride films have generally been ignored as a viable alternative gate dielectric to thermal oxide. The nitride have been characterized as too leaky and of exhibiting too much charge trapping to be an effective gate dielectric. In this work, we demonstrate a deposition and annealing sequence at 2.5nm that indicates that LPCVD nitride can be a viable alternative to thermal oxide as gate dielectric. The film shows no hysteresis after severe electrical stress [-3.5V for 100secs], Breakdown characteristics are superior to that of thermal oxide even on deep-submicron STI edge-intensive structures. The leakage characteristics are superior to that of thermal oxide. The drive current degradation and transconductance degradation is found to be less than 10% and procedures for alleviating this is discussed. The sub-threshold slopes of the dielectric are found to be equivalent to that of thermal oxides. The integration significance of these data is discussed.