Biblio

Ferroelectric capacitor memory devices with carbon-free Hf0.5Zr0.5O2 (HZO) ferroelectric films are fabricated and characterized. The HZO ferroelectric films are deposited by ALD at temperatures from 225 to 300°C, with HfCl4 and ZrCl4 as the precursors. Residual chlorine from the precursors is measured and studied systematically with various process temperatures. 10nm HZO films with optimal ALD growth temperature at 275°C exhibit remanent polarization of 25µC/cm2 and cycle endurance of 5×1011. Results will be compared with those from HZO films deposited with carbon containing metal-organic precursors.

Study on the effect of nanosecond laser anneal (NLA) induced crystallization of ferroelectric (FE) Si-doped hafnium oxide (HSO) material is reported. The laser energy density (0.3 J/cm2 to 1.3 J/cm2) and pulse count (1.0 to 30) variations are explored as pathways for the HSO based metal-ferroelectric-metal (MFM) capacitors. The increase in energy density shows transition toward ferroelectric film crystallization monitored by the remanent polarization (2Pr) and coercive field (2Ec). The NLA conditions show maximum 2Pr (\$\textbackslashsim 24\textbackslash \textbackslashmu\textbackslashmathrmC/\textbackslashtextcmˆ2\$) comparable to the values obtained from reference rapid thermal processing (RTP). Reliability dependence in terms of fatigue (107 cycles) of MFMs on NLA versus RTP crystallization anneal is highlighted. The NLA based MFMs shows improved fatigue cycling at high fields for the low energy densities compared to an RTP anneal. The maximum fatigue cycles to breakdown shows a characteristic dependence on the laser energy density and pulse count. Leakage current and dielectric breakdown of NLA based MFMs at the transition of amorphous to crystalline film state is reported. The role of NLA based anneal on ferroelectric film crystallization and MFM stack reliability is reported in reference with conventional RTP based anneal.