Effects of sputtering power on the formation of 5 nm thick ferroelectric nondoped HfO₂ gate insulator for MFSFET application

Abstract

In this research, the effects of sputtering power on the ferroelectric property of 5 nm thick ferroelectric nondoped HfO2 were investigated for metal-ferroelectric-semiconductor field-effect-transistor (MFSFET) application. The remnant polarization (2Pr) was increased to 5.9 μC/cm2, and the density of interface states (Dit) at silicon interface was effectively reduced to 1.8×1011 cm-2 eV-1 when the sputtering power was 50 W for 5 nm thick nondoped HfO2 formation. The largest Weibull slope (β) of 1.76 was extracted in Weibull distribution plot of the time dependent dielectric breakdown (TDDB) measurements, and excellent fatigue properties until 1010 cycles were realized. The memory window (MW) of 0.56 V was realized by the pulse amplitude and width of -1/6 V and 100 ms, respectively. Furthermore, the memory characteristic was expected to be maintained ever after 10 years of retention time.

Influence of XeCl excimer laser annealing on the ferroelectric nondoped HfO2 formation deposited on a Si(100) substrate

“…We have reported the reduction of SiO x IL thickness to 1.7 nm in the case of the 5 nm-thick HfO 2 with PMA at 500 °C. 28,32) We will investigate the effect of ELA for the HfO 2 with thinner SiO x IL next time.…”

“…[19][20][21][22] We have realized the ferroelectric nondoped HfO 2 (FeND-HfO 2 ) which was directly deposited on a Si substrate by RF magnetron sputtering utilizing strain-controlled deposition. [23][24][25][26][27][28][29][30][31][32][33][34] Although the annealing temperature was decreased to 500 °C, memory characteristics such as the MW are necessary to be improved. We have used rapid thermal annealing (RTA) for the crystallization of HfO 2 .…”

Kr-Plasma Sputtering for Pt Gate Electrode Deposition on MFSFET with 5 nm-Thick Ferroelectric Nondoped HfO₂ Gate Insulator for Analog Memory Application

“…The improvement of ferroelectric property is probably due to the improvement of interface property with reducing the plasma damage during Pt gate electrode deposition. In order to confirm the intrinsic P r of MFS diodes with 5 nm-thick ferroelectric nondoped HfO 2 film, double pulse measurement, so-called PUND measurement, was evaluated with the input pulses of ±5 V/5 µs [16]. The sum of capacitance charging current (J C ) and ferroelectric switching current (J FE ) is the total current component (J tot ) which is obtained from first pulse.…”

“…Figure 1 shows the experimental procedure for the MFS diodes and n-channel MFSFET with 5 nm-thick ferroelectric nondoped HfO 2 gate insulator utilizing conventional gate-last process [15], [16]. The schematic cross-sections and the plane-views of the fabricated MFS diodes and MFS-FET are also shown.…”

“…The reactive sputtering was carried out with Kr/O 2 gas flow ratio of 2.0/0.2 sccm. The gas pressure and sputtering power were 0.67 Pa and 50 W, respectively [16]. Subsequently, 20 nm thick Pt gate electrodes were deposited by Ar-and Kr-plasma sputtering without exposing to the air.…”