Abstract
A semiconductor device includes an insulating base layer, a semiconductor layer, an insulating layer, an isolation trench and a gettering site. The semiconductor layer and the insulating layer are disposed on the insulating base layer in sequence, and the isolation trench is disposed in the semiconductor layer and passes through the insulating layer. The isolation trench includes a first cross-section, a second cross-section and a third cross-section from top to bottom. The first cross-section is higher than the bottom surface of the insulating layer, and the second cross-section and the third cross-section are lower than the bottom surface of the insulating layer. The gettering site is disposed in the semiconductor layer and in contact with the isolation trench, and the vertex of the gettering site is lower than the second cross-section.