[14a-B7-1~4] 13.6 Semiconductor English Session

▲ [14a-B7-1] [Young Scientist Presentation Award Speech] Investigation of Bilayer HfN Gate Insulator Formed by ECR Plasma Sputtering

〇Nithi Atthi¹、Shun-ichiro Ohmi¹ (1.Tokyo Tech)

キーワード：Bilayer, Hafnium nitride, ECR plasma sputtering

We investigated the effects of PMA process on the performance of nMISFET with bilayer HfN_x gate insulator utilizing ECR plasma sputtering. By using the combination of PMA1 (before Al deposition) at 500°C/1 min with PMA2 (after Al deposition) at 300°C/30 min in N₂/4.9%H₂ forming-gas ambient, the EOT of 0.55 nm, leakage current density (@V_FB -1V) of 6.6x10^-5 A/cm² and density of interface states (D_it) of 5.6x10¹⁰ cm^-2eV^-1 were obtained. The saturation mobility has increased from 47 to 81 cm²/(Vs) compared to the device fabricated with PMA1 at 500°C/10 min. Therefore, the combination of PMA1 and PMA2 processes in N₂/4.9%H₂ ambient showed the suppression of hysteresis width in C-V from 184 to 54 mV, which leads to the improvement of the nMISFET characteristics.