| 摘要 |
PURPOSE:To obtain intrinsic gettering effect by a constitution wherein N<+> layer and N<-> or N layer in which internal defect is generated exist on a main surface of a wafer alternately and N<+> layer is exposed on the main surface. CONSTITUTION:In a substrate N<+> layer 1 and N or N<-> layer 2 exist alternately and on a main surface 3 of the substrate the layer 1 is exposed. In addition, the layer 2 has 10X10<17>/cm<3> of oxygen among lattice so that internal defect can be caused by some proper heat treatment. In this case internal defect is not caused in the layer 1 but, the layer 2 existing alternately generates intrinsic gettering (IG) effect. On whole surface of such substrate, epitaxial layer 4 is grown to fabricate the device. Heavy metal impurities produced by processing pollution at this time are effected gettering by the layer 2 composed of plural layers, while carriers caused by alpha rays or latch-up are recombined in the layer 1 right under the layer 4 to be brought to extinction. |
