[22p-A307-1~17] CS.7 Code-sharing Session of 6.1 & 13.3 & 13.5

▼ [22p-A307-10] Investigation of the etching process for Pt gate electrode on the ferroelectric property of 5 nm thick nondoped HfO₂ thin films

〇(DC)JoongWon Shin¹, Masakazu Tanuma¹, Shun-ichiro Ohmi¹ (1.Tokyo Inst. of Technol.)

Keywords:5 nm thick ferroelectric nondoped HfO2, Pt gate electrode, Wet etching process

Ferroelectric HfO₂ is considered as a promising candidate for metal-ferroelectric-semiconductor field-effect-transistors (MFSFETs) due to its Si compatibility and scalability. Previously, we realized MFSFET with 5 nm thick nondoped HfO₂ gate insulator and Pt gate electrode utilizing conventional gate-last process. However, wet etching process of Pt gate electrode utilizing aqua regia has an issue from the process damage point of view.
In this study, we investigated the etching process for Pt gate electrode utilizing field oxide on the ferroelectric property of 5 nm thick nondoped HfO₂.The largest 2P_r of 3.9 µC/cm² was observed in case of MFS diode with field oxide at V_max-V_min of 10 V. Furthermore, the field oxide was effective to reduce the D_it from 1.1×10¹² cm^-2eV^-1 to 1.2×10¹¹ cm^-2eV^-1 with decreasing the wet etching damage.
Therefore, the precise control of etching for Pt gate electrode is important to improve the memory characteristic of MFSFET.