Structures and methods for reducing backside polysilicon peeling are disclosed. A structure includes a substrate having a first side and a second opposite side, a first dielectric layer on the second side of the substrate extending in a direction from an edge of the substrate towards a center of the substrate, a high-k layer on the first dielectric layer, and a polysilicon layer on the high-k layer. The first dielectric layer has a first innermost sidewall relative to the center of the substrate, and the high-k layer has a second innermost sidewall relative to the center of the substrate. The second innermost sidewall is within 2 millimeters from the first innermost sidewall in a direction parallel to the second side. The polysilicon layer extends towards the center of the substrate further than the first innermost sidewall.