Method for producing a substrate

A method for producing a substrate, comprising:

• applying a semiconductor layer, the semiconductor layer having a region of thicker thickness and a region of thinner thickness, wherein the semiconductor layer is formed at least partly by means of selective epitaxy, wherein the step of applying the semiconductor layer comprises:
• forming a thin first semiconductor partial layer on an auxiliary carrier layer;
• depositing a masking layer made of an insulator material on at least one region of the thin first semiconductor partial layer;
• and
• forming a second semiconductor partial layer on any regions of the thin first semiconductor partial layer which are not covered by the masking layer;
• applying an insulator layer on the semiconductor layer, the insulator layer having a region of thicker thickness and a region of thinner thickness,
• wherein the insulator layer is applied such that the region of thinner thickness of the insulator layer contacts the region of thicker thickness of the semiconductor layer, and the region of thicker thickness of the insulator layer contacts the region of thinner thickness of the semiconductor layer, such that the surface of the semiconductor layer facing away from the insulator layer is planar, and
• wherein the step of applying the insulator layer comprises:
• depositing a first insulator partial layer on an entire surface of the substrate;
• and
• planarizing the first insulator partial layer;
• applying a carrier layer to the insulator layer, wherein the step of applying the carrier layer comprises the steps of:
• providing a carrier substrate;
• applying a second insulator partial layer on the carrier substrate;
• and
• bonding the carrier substrate and the second insulator partial layer to the planarized surface of the first insulator partial layer such that the second insulator partial layer is arranged on the first insulator partial layer, and
• removing the auxiliary carrier layer.