| 摘要 |
PURPOSE:To form epitaxial growth layers with little generation of auto doping by a method wherein an epitaxial layer is formed after reduction of the drift of impurities from the semiconductor substrate in vapor phase. CONSTITUTION:A semiconductor substrate 11 having a high impurity concentration is heated to a prescribed epitaxial growing temperature e.g. 1,050 deg.C, and the first epitaxial layer 12 is formed by supplying the H2 carrier gas with the reaction gas made of SiH4 or the like, thus coating the surface of the semiconductor substrate 11. This inhibits the evaporation of impurities from the semiconductor substrate 11 in the later process. Thereafter, the temperature of the substrate 11 is increased to e.g. 700 deg.C and kept while H2 gas is flowed. This manner reduces the width of a gas drift layer 13' and causes impurity atoms 14 having been drifted in this region to disperse together with H2 gas currents 15. There, the epitaxial growing temperature of the substrate 11 is increased again to 1,050 deg.C, and the second epitaxial layer is formed with a required thickness by supplying the H2 carrier gas with the reaction gas such as SiH4 or PH3. |
