Fabrication and characterization of metal-ferroelectric-insulator-Si diodes and transistors with different HfSiON buffer layer thickness

Abstract

Metal-ferroelectric-insulator-Si (MFIS) structures using HfSiON as buffer layers were fabricated, and the impact of buffer layer thickness on the electrical properties of the MFIS devices was investigated. HfSiON films with thickness ranging from 1 to 4 nm were deposited by electron beam evaporation, which exhibited much reduced leakage current when compared to that of SiO2 with the same equivalent oxide thickness. From the viewpoint of polarization and charge injection, the flatband voltage and memory window width dependent on the sweeping voltages were discussed for the MFIS diodes with 1-, 2-, and 4-nm-thick HfSiON buffer layers. Small leakage current as well as excellent long-term data retention characteristics were found for all of these samples. It was also found that MFIS diodes with 2-nm-thick HfSiON buffer layer have the largest memory window width. Ferroelectric-gate transistors fabricated with a Pt/SBT(300nm)/HfSiON (2 nm)/Si gate structure showed a memory window of 0.8 V and a high drain current on/off ratio of 108 for the gate voltage sweep between +4 and −4 V. All of these excellent electrical properties proved that HfSiON acts as an excellent barrier for suppressing both leakage current and atomic interdiffusion.

Capacitive and RRAM Forming-Free Memory Behavior of Electron-Beam Deposited Ta2O5 Thin Film for Nonvolatile Memory Application

“…Under sweeping gate voltages from ±1 to ±10 V, memory windows increase from 1.2 to 7.9 V, respectively. The increase in the memory window with the higher gate bias is attributed to extra charges injected into the devices. , Furthermore, the density of trapped charges per area ( N ) can be determined using eq where A denotes the device area, Δ V FB is the hysteresis, q defines the charge of an electron, and C ox is the accumulation capacitance.…”

“…The increase in the memory window with the higher gate bias is attributed to extra charges injected into the devices. 42,43 Furthermore, the density of trapped charges per area (N) can be determined using eq 3. 44 N C V qA…”

Integration of Ferroelectric Materials: An Ultimate Solution for Next-Generation Computing and Storage Devices

“…Before 2000, numerous reports were focused on ferroelectricity in perovskites, such as LiNbO 3 , YMnO 3 , PbTiO 3 , and (Ba,Sr)­TiO 3 . From 2000 onward, research on ferroelectric materials was intensive, primarily on SrBi 2 Ta 2 O 9 (SBT), − (Bi,La) 4 Ti 3 O 9 (BLT), − Pb­(Zr,Ti)­O 3 (PZT), − and so on due to their excellent fatigue and leakage characteristics. From the above, PZT emerged as a promising candidate due to its high P r and low crystallization temperature and was widely adopted in commercial 1T-1C FeRAM applications. , However, polycrystalline PZT or PZT with Pt electrodes suffers from fatigue (<10 8 cycles).…”