Low-Voltage Operation of MFSFET with Ferroelectric Nondoped HfO2 Formed by Kr/O2-Plasma Sputtering

Ferroelectric nondoped HfO 2 has advantages compared to the doped HfO 2 in the reduction of crystallization temperature and threshold voltage (V TH ) control for the Metal-Ferroelectrics-Si FET (MFSFET) application [1] , [2] . It is usually difficult to form the ferroelectric nondoped HfO 2 on the Si substrates. We have reported that the ferroelectric nondoped HfO 2 formation on the Si(100) substrates by controlling the Ar/O 2 flow ratio during the reactive sputtering followed by the annealing below 600°C [3] - [5] . However, the improvement of ferroelectric characteristics is necessary especially below the thickness of 10 nm for the scaling. In this paper, we have investigated the effect of Kr/O 2 -plasma sputtering for the ferroelectric nondoped HfO 2 formation below 10 nm for the MFSFET applications.