Physical and electrical analysis of silicon dioxide thin films produced by electron-cyclotron resonance chemical-vapour deposition

✍ Scribed by D. Landheer; L.-Å. Ragnarsson; S. Belkouch

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 685 KB
• Volume: 36
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(97)00014-2

✦ Synopsis

High-quality silicon dioxide films have been deposited in the temperature range 150-425 °C by electron-cyclotron resonance chemical-vapour deposition (ECR-CVD) using an oxygen plasma with silane introduced downstream. The interface state densities of 10 nm thick films measured by the high-low frequency CV method have values in the range of 3-5xl01°eV'tcm "2. "lhirty secood anneals in flowing nitrogen in the temperature range 850-950 °C reduced the values to below the sensitivity limit, 2x10 t° eV'lem "2. The electrical performance of the films has been correlated with their silanol content as determined by Fourier-transform infrared spectroscopy and the surface and interface roughness as determined by atomic-force microscopy. Negative Fowler-Nordheim stress measurements performed on Al-gated capacitors with 19.1 nm thick films deposited at 300 °C and annealed for 30 s at 900 °C exhibited positive charging and interface state generation rates larger than as those of Al-gated capacitors with thermal oxides. The excess generation of both the positive charge and interface states can be described by processes with cross-sections of 3-4x10 "t9 cm 2. The nature of the interface traps and the prospects for reducing their concentration by polysilicon gate processing are discussed.