Application of fluorinated SiO2 interlayer dielectrics for ferroelectric memory

Fluorine-doped silicon oxide (SiOF) as interlayer dielectric (ILD) was depo sited over PZT capacitors by electron cyclotron resonance (ECR) chemical va por deposition using SiF4 and N2O gases. In the conventional deposition of SiO2 ILD layer using hydrogen-contained source gases, the properties of fer roelectric capacitors are known to be degraded during the formation of SiO2 layer. In this study, we examined the degradation of electrical properties of SiOF-deposited PZT capacitors. The remnant polarization and leakage cur rents were not degraded after the deposition of SiOF We observed that the f luorine atoms were not diffused into the metal electrode in both cases of t he SiOF deposited PZT capacitors and post-deposition annealed capacitors. T he SiOF films deposited in the high CF4 flow rate exhibited rough columnar structure on the metal electrodes. We can successfully deposit SiOF in a sm ooth morphology by introducing TiO(2)buffer layer or using the novel deposi tion method of changing the SiF4 flow rate, namely two-layer-deposition met hod.