Spinning at 3000 rpm will yield a film about 3200 angstroms thick. Film deposited by spraying will exhibit excellent leveling characteristics. Film thickness obtained by spraying will depend upon such variable as the liquid flow rates, determined by liquid pressure, and rate of travel of the substrates under the spray nozzle.
Films deposited by spinning are ready for diffusion.
Films deposited by spraying should be heated to 40-50 o C to insure drying. After diffusion films which remain on the wafer surface are readily etched away in dilute HF solution. Cleaning All apparatus used with this solution may be cleaned in warm water. The solution is essentially non-flammable. The phosphorous concentration is such that the material should not be ingested.