Methods of forming polysilicon-filled deep trenches for an eDRAM are provided. The method may include forming a plurality of polysilicon-filled deep trenches in a substrate. An epitaxy-retarding dopant is introduced to an upper portion of the trenches. A plurality of fins are then formed over the substrate, with each polysilicon-filled deep trench including a corresponding fin extending thereover. A silicon layer is epitaxially grown over at least the polysilicon-filled deep trench. The dopant in the polysilicon-filled deep trenches acts to control the epitaxial growth of the silicon layer, diminishing or preventing shorts to adjacent fins and/or deep trenches at advanced technology nodes.