PURPOSE: To obtain stable gettering capability which can restrain dislocation of process induction and crystal defect of OSF or the like, relieve adverse influence caused by substrate structure upon device characteritics, prevent the warp of a substrate, and improve and stabilize the manufacturing yield of a device.

CONSTITUTION: A dielectric isolation semiconductor substrate consists of the following; a first thick semiconductor layer 21 turning to a base, a first and a second gettering layers 22a, 22b formed on both main surfaces of the first semiconductor layer 21, a first and a second insulating layers 23a, 23b formed on both outside main surfaces of the gettering layers 22a, 22b, and a second semiconductor layer 24 of an active layer which is bonded to the outside main surface of the first insulating layer 23a. A substrate formed by an EG method is a substrate wherein two wafers hold a gettering layer between them and are stuck in a body. The substrate is worked and polished to have a specified thickness wherein the gettering layer is positioned at the center part of the thickness direction.