Comparison of defect structure in N2O- and NH3-nitrided oxide dielectrics

Publisher Website
Google Scholar
Abstract
Electron spin resonance spectroscopy is used to identify and compare point defects in N2O‐nitrided, NH3‐nitrided, and conventional SiO2 films. We detect only three types of defects in these dielectrics. Pb centers, the primary source of interface states in Si/SiO2 systems under all technologically significant circumstances, appear in all three dielectrics. Both N2O and NH3 nitridation result in higher as‐processed Pb interface defect densities, but lower radiation‐induced Pb defect generation. Thus N2O nitridation appears capable, as does NH3 nitridation, of providing reduced radiation‐induced interface state generation. In addition, both nitridations appear capable of lowering the number of radiation‐induced E’ centers, the dominant hole trap in conventional thermal oxides. NH3 nitridation, however, appears to offer greater resistance to radiation‐induced generation of these traps. NH3 nitridation also results in a large number of bridging nitrogen centers, and strong evidence indicates that the bridging nitrogen centers are the dominant electron trap in NH3‐nitrided and ‐reoxidized nitrided oxide films. These defects are absent in N2O‐nitrided films, which are known to exhibit reduced levels of electron trapping.