Title :
Anomalous leakage current in silicon oxynitride thin films grown by microwave excited nitrogen plasma nitridation
Author :
Perera, Rohana ; Ikeda, Akihiro ; Hattori, Reiji ; Kuroki, Yukinori
Author_Institution :
Dept. of Electron., Kyushu Univ., Fukuoka, Japan
Abstract :
Silicon oxynitride (SiON) has emerged as a better gate dielectric material to replace ultra-thin gate SiO2 in scaled down metal-oxide-semiconductor (MOS) devices. The present study investigates the leakage current in SiON grown by a plasma-based process. Thin films of SiON (6 nm) were grown on Si substrates by nitriding rapid thermally grown SiO2 layers in a low-energy, microwave excited nitrogen plasma and by subsequent re-oxidation; and the resulting films were characterized in Al/SiON/p-Si MOS structures under atmospheric, vacuum and low temperature conditions. The analysis of the current-voltage (I-V) characteristics obtained under atmospheric conditions shows an enhanced leakage current in the pre-Fowler-Nordheim region of 4∼8 MV/cm oxide field range. However, I-V characterization in vacuum showed the complete removal of this additional current component. This current was found to be not due to a charging/capacitive effect. It is speculated that this additional mid-ox ide-field leakage current could possibly be due to a conducting pathway given rise to by interaction of atmospheric gases/water molecules with the plasma induced defects on the oxynitride film.
Keywords :
MOS capacitors; aluminium; dielectric materials; dielectric thin films; elemental semiconductors; leakage currents; nitridation; silicon; silicon compounds; Al-SiON-Si; Al/SiON/Si MOS structures; MOS devices; Si substrates; anomalous leakage current; atmospheric gases/water molecules interaction; charging/capacitive effect; current voltage characteristics; gate dielectric material; metal-oxide-semiconductor devices; microwave excited nitrogen plasma nitridation; plasma induced defects; preFowler-Nordheim region; rapid thermally grown SiO2 layers; reoxidation; silicon oxynitride thin films; ultra-thin gate SiO2; Dielectric materials; Dielectric thin films; Leakage current; Microwave devices; Nitrogen; Plasma devices; Plasma materials processing; Plasma temperature; Semiconductor thin films; Silicon;
Conference_Titel :
Properties and Applications of Dielectric Materials, 2003. Proceedings of the 7th International Conference on
Print_ISBN :
0-7803-7725-7
DOI :
10.1109/ICPADM.2003.1218611
