Polysilazane Precursor Used for Formation of Oxidized Insulator

Abstract

We report on SiO₂ film formation using Polysilazane precursor treated with remote oxygen plasma and high-pressure H₂O vapor heating. Polysilazane precursor films with a thickness of 130 nm were formed on silicon substrates by spin coating method. They were annealed at 350°C in remote oxygen plasma at a pressure of 2.0×10⁻² Pa and a 13.56×106 Hz radio frequency power of 300 W for 3h followed by 1.3×106-Pa-H₂O vapor heating at 260°C for 3 h. Polysilazane precursor films were entirely oxidized by high-pressure H₂O vapor heat treatment, and the density of Si-N bonding and Si-H bonding in Polysilazane precursor films were effectively dissociated by the combination of high-pressure H₂O vapor heat treatment with remote oxygen plasma treatment. While MOS(Metal-Oxide-semiconductor) capacitors fabricated only by high-pressure H₂O vapor heat treatment had a high specific dielectric constant of 6.1, a fixed oxide charge density of 1.3×10¹² cm⁻² and a density of interface trap of 5.4×10¹¹ cm⁻²eV⁻¹, the remote oxygen plasma treatment followed by high-pressure H₂O vapor heat treatment allowed us to reduce them to 4.1 and 1.6×10¹¹ cm⁻², 4.2×10¹⁰ cm⁻²eV⁻¹, respectively.