| 摘要 |
PURPOSE:To suit the thin film to miniaturization and decrease in temperature of semiconductors by forming the thin film with varying the ratio of nitrogen to silicon continuously or gradually from silicon to silicon nitride stoichiometrically. CONSTITUTION:The condition for forming typical silicon nitride, for example, is 700-800 deg.C SiH2Cl2 30-80SCCM, NH3 300-1,000SCCM and the deposition rate is 20-40Angstrom /min. A flow of NH3 for SiH2Cl2 is increased with respect to time, a ratio of silicon and nitrogen changes stoichiometrically. At last, a perfect silicon nitride is formed and a film thickness only of silicon nitride is endurable for oxidation by a LOCOS method sufficiently. Accordingly, the total film thickness becomes thicker than the conventional silicon nitride film thickness, but the thickness for a silicon oxide film to be formed as a base is not necessary so that the thickness is nearly same. |
