HIGH-TEMPERATURE DEPOSITION AND EVALUATION OF PHOSPHORUS-DOPED OR BORON-DOPED SILICON DIOXIDE FILMS

Three different reactions for depositing phosphorus- or boron-doped silicon dioxide at high temperatures have been investigated: the reaction of silane and phosphine or diborane with nitrous oxide at 700°-900° C; with nitric oxide at 700°-900°C; and with carbon dioxide and hydrogen at 900°C. The reactions with nitrous oxide are suitable for routine depositions on silicon-integrated circuits. The reactions with nitric oxide are very sensitive to oxygen impurities which cause the film composition to vary. The reactions with carbon dioxide and hydrogen produce very little dopant in the film. The deposition rate and the film composition for the nitrous oxide reaction are satisfactorily explained by the Langmuir-Hinshelwood model for heterogeneous reactions. The films from the nitrous oxide reactions have been evaluated by measuring the refractive index, etch rate, defect density, infrared spectra, step coverage, and diffusion properties. The major differences between these films and films deposited at lower temperatures are the lower etch rate, decreased defect density, and improved step coverage for the films deposited at high temperatures. © 1979, The Electrochemical Society, Inc. All rights reserved.