Effect of Forming Gas Furnace Annealing on the Ferroelectricity and Wake-Up Effect of Hf_0.5Zr_0.5O₂ Thin Films

Abstract

The effect of furnace annealing on the ferroelectricity, leakage current, and wake-up effect in Hf0.5Zr0.5O2 (HZO) ultrathin film is studied as a function of furnace annealing temperature and gas environment after crystallizing the films with rapid thermal annealing in the presence of a TiN capping electrode. HZO films are deposited using atomic layer deposition in a Ge-HZO-TiN stack with Pt as the top contact electrode. The increment in the remanent polarization (Pr) is higher when the films are furnace annealed in the forming gas ambient. Forming gas furnace annealed films show an order of magnitude less leakage current as compared to the nitrogen annealed films. Dynamic hysteresis current measurements of the HZO ultrathin films show a faster merging of the four switching peaks after cycling the virgin forming gas furnace annealed films. H-incorporation during forming gas furnace annealing does not degrade the ferroelectric properties of HZO ultrathin films unlike conventional ferroelectrics, such as PZT or SBT. Higher Pr, lower leakage current, and an improved wake-up effect of the HZO ultrathin films show its resistance to degradation by forming gas furnace annealing, which makes ferroelectric HfO2 an ideal material for next-generation ferroelectric memory devices.

A Comprehensive Study on the Effect of TiN Top and Bottom Electrodes on Atomic Layer Deposited Ferroelectric Hf0.5Zr0.5O2 Thin Films

“…However, TiN electrodes can act as a barrier layer to hydrogen diffusion into the ferroelectric HZO film [ 14 , 26 ]. As expected, there was no degradation in the ferroelectric properties observed in the HZO films using TiN electrodes due to FGA, which is consistent with previously reported studies [ 26 , 27 ]. In those studies, HZO films with Pt electrodes were reported to degrade ferroelectric properties during FGA due to hydrogen incorporation [ 26 ].…”

Effect of Process Temperature on Density and Electrical Characteristics of Hf0.5Zr0.5O2 Thin Films Prepared by Plasma-Enhanced Atomic Layer Deposition

“…In addition, as the annealing temperature increases, the wake-up effect is improved; notably, the sample annealed at 700 °C shows the best improvement of the wake-up effect. However, the sample annealed at 700 °C showed the lowest fatigue endurance (1.6 × 10 6 cycles), which is attributed to diffusion at the electrode interface [ 45 , 46 ].…”

Wake‐Up Effect in HfO2‐Based Ferroelectric Films

“…Shekhawat et al adjusted the annealing conditions and changed the material of BE simultaneously. [81] They added a forming gas annealing method following rapid thermal annealing with a N 2 (96%)/H 2 (4%) mixed atmosphere. The forming gas annealing process with H 2 can introduce the H element and passivate the dangling bonds, which have been proven to be harmful to conventional ferroelectric materials such as PZT.…”