Structures and methods for reducing process charging damages are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a polysilicon region and an etch stop layer. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, and a buried layer arranged over the insulation layer. The polysilicon region extends downward from an upper surface of the buried layer and terminates in the handle layer. The etch stop layer is located on the substrate. The etch stop layer is in contact with both the substrate and the polysilicon region.