A memory device comprising a doped conductive polycrystalline layer having an electrically resistive portion, is described herein. By way of example, ion implantation to a subset of the conductive polycrystalline layer can degrade and modify the polycrystalline layer, forming the electrically resistive portion. The electrically resistive portion can include resistive switching properties facilitating digital information storage. Parametric control of the ion implantation can facilitate control over corresponding resistive switching properties of the resistive portion. For example, a projected range or depth of the ion implantation can be controlled, allowing for preferential placement of atoms in the resistive portion, and fine-tuning of a forming voltage of the memory device. As another example, dose and number of atoms implanted, type of atoms or ions that are implanted, the conductive polycrystalline material used, and so forth, can facilitate control over switching characteristics of the memory device.