Retention Reliability Improvement of SONOS Non-volatile Memory with N2O Oxidation Tunnel Oxide

The reliability characteristics of polysilicon-oxide-nitride-oxide -silicon (SONOS) devices with different thin tunnel oxides are studied. The tunnel oxynitride growth in a pure N ₂ O ambient with high temperature has better performance than in a dry oxidation with N ₂ annealing treatment including leakage current, programming speed, read disturb and retention. Besides, the surface roughness and interface states between tunnel oxide and Si substrate are also observed by atomic force microscope (AFM) technique and charge-pumping method to evaluate interfacial nitrogen incorporation. The results show that the reliability of data retention obtained a significant improvement while maintaining good programming/erase performance and can provide a straightforward way of reliability improvement for future flash memory application