Investigating Theoretically Doping Silicon Nitride Layer Of SONOS Device By DFT Method

Because the portable electrical products are more and more popular, such as notebook, mobile telephone and digital camera, Non-Volatile Memory (NVM) devices have played important roles in development of memory devices. The SONOS memory, which was invented more than thirty years ago, has gained increasing interest in the semiconductor industry to cope with the formidable challenge of scaling. The SONOS memory offers advantages of better endurance, low-voltage low-power operation and a simple fabrication process compatible with standard CMOS technology. But charge leakage through ultra-thin tunnel oxides has been a concern for long-term retention of SONOS devices. Therefore, improving data retention characteristics of SONOS devices is critical for its successful scaling and extensive usage.In this thesis, according to experimental research on amorphous silicon nitride and amorphous silicon nitride doped by oxygen or fluorin, simple cluster models of defects in amorphous silicon nitride with and without doping special element, such as oxygen, sulfur, phosphorus, fluorine or chlorine are built. And by density functional theory (DFT), positions of all atoms of cluster are optimized, and energies of these clusters are calculated.