Role of high energy photons in dual spectral source rapid isothermal CVD

Abstract

The use of tungsten halogen lamps and the deuterium lamp as the source of thermal and optical energies has been exploited to deposit thin films of Ta₂O₅ on Si and conducting substrates. The leakage current densities are as low as 10⁻¹⁰ A/cm² for gate voltage under 5V. Photons in visible, ultraviolet, and vacuum ultraviolet (λ<800 nm) regions provide higher bulk and surface diffusion coefficients as well as reduced activation energy for the chemical process involved in the chemical vapor deposition process. The low thermal mass of the substrate provides limited reaction processing capability. The photochemical and photophysical processes allow the participating atoms and molecules to adjust their bond geometries and occupy sites which result in overall reduction of stress and strain energy and provide materials with overall low microscopic defects at low processing temperature and with high throughput. New experimental results of Al-Ta₂O₅-Si₃N₄-poly Si-Al structure are presented. The leakage current-voltage characteristics are better than those reported by other researchers.