Characterization of Plasma‐Deposited Silicon Dioxide

Silicon dioxide films have been deposited by reacting silane and nitrous oxide in a parallel‐plate, radial flow, plasma reactor. Deposition parameters (temperature, power, and gas composition) have been systematically varied, and the films characterized by measuring the infrared spectra, deposition rate, density, etch rate, stress, refractive index, step coverage, breakdown voltage, and annealing behavior. The films, deposited at 100°–340°C and at rates of 200–360 Å/min, contain 2–9 a/o H bonded as , , and . The films have densities of about 2.3 g/cm 3 , refractive indexes of about 1.47, a compressive stress usually less than , and etch rates about twelve times faster than thermally grown silicon dioxide. Films deposited below 200°C or at high power etch nonuniformly with part of the film etching very fast, possibly indicating a two‐phase mixture. The step coverage is not conformal and the films are thin along vertical step walls. The films breakdown at fields of 4–10 MV/cm. During annealing in air at temperatures up to 400°C, the films lose hydrogen and become less dense, but do not crack. The properties of the plasma‐deposited silicon dioxide are strongly dependent on the specific deposition conditions. In addition, simple correlations between the properties do not exist. Thus in characterizing plasma deposited silicon dioxide, the exact deposition conditions must be specified and all the film properties of interest must be measured.