Laser ablation can be used to form a trench within at least a blanket layer of a stressor layer that is atop a base substrate. A non-ablated portion of the stressor layer has an edge that defines the edge of the material layer region to be spalled. Laser ablation can also be used to form a trench within a blanket material stack including at least a plating seed layer. A stressor layer is formed on the non-ablated portions of the material stack and one portion of the stressor layer has an edge that defines the edge of the material layer region to be spalled. Laser ablation can be further used to form a trench that extends through a blanket stressor layer and into the base substrate itself. The trench has an edge that defines the edge of the material layer region to be spalled.