The Deposition of Silicon Dioxide Films at Reduced Pressure

Films of silicon dioxide have been deposited on silicon substrates by decomposing tetraethoxysilane (TEOS) at 700°–750°C in a reduced pressure CVD reactor. The deposition rate is 200–300 Å/min. The thickness uniformity is better than ±1% over a deposition zone capable of holding 100 wafers. The step coverage is conformal, the defect density is very low, and the film stress is compressive and low. The refractive index, infrared spectrum, and film density appear normal for deposited silicon dioxide. The addition of phosphorus compounds causes the deposition rate to increase and the thickness uniformity to degrade. Consequently, this reaction is not suitable for depositing phosphorus‐doped films for integrated circuit applications; however, this reaction appears to be a very good process for depositing undoped films of silicon dioxide.