Abstract
Plasma charging effects on the gate insulator of high dielectric constant (k) material in MOS devices was investigated because of the different trap-assisted conduction mechanism from that in the oxide. Plasma-induced degradation in gate leakage current and time to breakdown is clearly observed in this work. MOS device with Si 3 N 4 film seems to have smaller degradation of gate leakage current while it suffers shorter time to breakdown as compared to Ta 2 O 5 samples. For devices with Ta 2 O 5 film, a larger physical thickness suffers more reliability degradation from plasma charging damage because of more traps in the Ta 2 O 5 bulk. Thus, a smaller physical thickness of high-k dielectric film is favorable for sub-micron MOS devices of ULSI application.