| 摘要 |
PURPOSE:To prevent defects in a laminated layer for a semiconductor device by using a substrate having defects of number larger than 10<5>/cm<2> even after processing it for 18hr at 1,050 deg.C by heating an Si substrate containing a predetermined density of oxygen at 600-900 deg.C for predetermined time to produce defects of number larger than 10<5>/cm<2>. CONSTITUTION:Defects 6 existed in the crystal of a substrate 1 (round bottom pits) have close relationship with defects formed in an epitaxial layer 4 of laminated layer for a semiconductor device. If the round bottom pits are higher in number than 10<5>/cm<2> when heating the substrate at 1,050 deg.C for 18hr in an N2, ethcing it and observing it by an optical microscope, the defects in the epitaxial layer 4 of laminated layer fall within an allowable range. This high temperature process enlarges the miniature defects in the substrate to a size capable of observing them. The more the round bottom pits are increased, the less the defects in the epitaxial layer are decreased. Since the round bottom pit density is varied in accordance with the density of oxygen, when the substrate is heated at low temperature of 600- 900 deg.C, the round bottom pit density is increased without increasing the density of the oxygen in the substrate so as to prevent the defects in the epitaxial layer of the laminated layer.
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