Dielectric-on-Dielectric Achieved on SiO2in Preference to W by Water-free Chemical Vapor Depositions with Aniline Passivation

Selective and smooth dielectric-on-dielectric was achieved by water-free single-precursor chemical vapor deposition (CVD) processes with the help of aniline passivation. Aniline selective passivation was demonstrated on W surfaces in preference to SiO2 at 250, 300, and 330 °C. After aniline passivation, selective HfO2, Al2O3, and TiO2 were deposited only on the HF-cleaned SiO2 surface by water-free single-precursor CVD using hafnium tert-butoxide Hf(OtBu)4, aluminum-tri-sec-butoxide (ATSB), and titanium isopropoxide Ti(OiPr)4 as the precursor reactants, respectively. Hf(OtBu)4 and Ti(OiPr)4 single-precursor CVD was carried out at 300 °C, while the ATSB CVD process was conducted at 330 °C. HfO2 and Al2O3 nanoselectivity tests were performed on W/SiO2 patterned samples. Transmission electron microscopy images of the W/SiO2 patterned samples after deposition demonstrated nanoselectivity and low surface roughness of HfO2 and Al2O3 deposition on the SiO2 regions only.