Enhanced reliability for low-temperature gate dielectric of MOS devices by N₂O or NO plasma nitridation

Silicon MOS capacitors fabricated solely by low-temperature processes (under 600 °C) are treated with nitridation using N₂O or NO plasma. Their properties are investigated at room temperature under high-field stress. It is found that both kinds of plasmas are effective in improving the gate-oxide hardness against stress-induced damage, which is characterized by a smaller shift in flatband voltage and smaller increase in interface states after the stress. Moreover, NO-nitrided device shows better performance than N₂O-nitrided one. These results show that plasma nitridation has positive effects on the reliability of low-temperature-fabricated devices, which play an important role in flat-panel display systems on glass.