Gate dielectric nitrization and effect on changes in the density of interlayer states of MOS structures

Abstract

The processes occurring in the silicon-oxygen-nitrogen system are of great practical importance, since dielectric layers made from materials of this system are widely used as barriers to the penetration of impurities, elements of storage capacitors, field insulating layers, etc. Interest in the creation of such dielectrics has increased in connection with the use of the rapid thermal annealing stage in technological processes, which are accompanied by the appearance of fast surface states and mechanical stresses on the interface. As a result of the study, it was determined that the change in the threshold voltage in MDS structures is associated with the capture of electrons by the traps formed in the bulk of the semiconductor. MDS structures with nitrided oxide have better stability than conventional oxide. Studies have shown that the suppression of the formation of states at the interface depends on the degree of nitriding. The characteristics of MDS structures under the influence of irradiation substantially depend on the temperature and duration of fast thermal nitrization.

Keywords

• metal–dielectric–semiconductor
• silicon oxynitride
• nitrization
• gate dielectric
• silicon dioxide
• heat treatment