Approximately 13 nm thick HfO2 films are grown on Si wafers by atomic layer deposition under different ozone concentrations at 280 °C using Hf[N(Et)(Me)]4 as Hf precursor.

The effects of forming gas annealing (FGA) on the ferroelectric properties of Hf0.5Zr0.5O2 (HZO) films were examined. Although the H-incorporation during FGA degrades the ferroelectric properties of Hf0.5Zr0.5O2 films, the degree of degradation was much lower compared with other ferroelectrics, such as Pb(Zr,Ti)O3. Pt worked as a catalyst for H-incorporation, and maximum 2Pr loss of ∼40% occurred. However, the insertion of a ∼20-nm-thick TiN layer between Pt and Hf0.5Zr0.5O2 decreased the degradation to ∼12%. Hf0.5Zr0.5O2 is more resistant to degradation by FGA compared with the conventional ferroelectrics, which is a highly promising result for next-generation ferroelectric memory.

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The effects of Pt and RuO2 top electrodes on the electrical properties of capacitors with Al-doped TiO2 (ATO) films grown on the RuO2 bottom electrode by an atomic layer deposition method were examined. The rutile phase ATO films with high bulk dielectric constant (>80) were well-grown because of the local epitaxial relationship with the rutile structured RuO2 bottom electrode. However, the interface between top electrode and ATO was damaged during the sputtering process of the top electrode, resulting in the decrease in the dielectric constant. Postmetallization annealing at 400 °C was performed to mitigate the sputtering damage. During the postmetallization annealing, the ATO layer near the RuO2 top electrode/ATO interface was well-crystallized because of the structural compatibility between RuO2 and rutile ATO, while the ATO layer near the Pt top electrode/ATO interface still exhibited an amorphous-like structure. Despite the same thickness of the ATO films, therefore, the capacitors with RuO2 top electrodes showed higher capacitance compared to the capacitors with Pt top electrodes. Eventually, an extremely low equivalent oxide thickness of 0.37 nm with low enough leakage current density (<1 × 10(-7) A/cm(2) at 0.8 V) and physical thickness of 8.7 nm for the next-generation dynamic random access memory was achieved from ATO films with RuO2 top electrodes.

Variations in the (a) growth rate and (b) film density, measured via the XRR of the HfO2 films with O3 and H2O oxidants as a function of Ts (160–360 °C).