Quality Improvement in LPCVD Silicon Nitrides by Anodic and Rapid Thermal Oxidations

Low-pressure chemical vapor deposition (LPCVD) quality presents a dramatic improvement after oxidation. Both liquid-phase anodic oxidation and rapid thermal oxidation were studied in this work. After oxidation, layers grown on the surface, and oxygen incorporated into the layer were observed. The nonstoichiometric bonding, i.e. , Si dangling bonds, and crystalline Si were oxidized into or and the stoichiometric bonding maintained a higher- k property. In addition, more oxygen replacement of the imperfect Si-N bonds after anodic oxidation contributed to better improvement in suppressing gate leakage current.