Charge storage in PECVD silicon oxynitride layers

Results on charge storage in silicon oxynitride ranging from pure oxide to pure nitride are presented. Samples deposited in a radio-frequency plasma (RF) as well as those made in dual-frequency microwave/radio-frequency (MW/RF) plasma are investigated. At room temperature, most of the samples show quite satisfactory charge storage capability: during four months, almost no charge decay was observed for the best samples. Additional measurements at elevated humidities and temperatures show that in layers deposited in the dual-frequency mode, the charge stability improves with increasing oxygen content. Furthermore, the dual-frequency deposited samples have higher surface potential and improved charge retention compared to their radio-frequency counterparts. The layers could be charged up to fields of 400 MV/m