Methods for manufacturing a large number of memory cells, including: Providing a substrate (99) that includes an access circuit for the plurality of memory cells and that has a contact surface (100) with an array of conductive contact plugs (120, 141) connected to the access circuit; Forming a layer of bottom
electrode material (200) on the contact surface (100) of the substrate (99); Formation of
mask structures (201, 202) on the layer of bottom
electrode material (200); Preparing the
mask structures (201, 202) on the layer of bottom
electrode material (200) by
isotropic etching of the
mask structures (201, 202) to create a pattern of prepared mask structures (201A, 202A); Removal of material from the layer of bottom
electrode material (200) by
anisotropic etching using the prepared mask structures (201A, 202A) as an etch mask to form a pattern of electrode columns (210, 211) on corresponding conductive contact plugs (120, 141) in the field of conductive contact plugs (120, 141); Forming a layer of
dielectric material (212) covering the pattern of electrode columns (210, 211) and exposed sections of the contact surface (100); Planarizing the layer of
dielectric material (212) and the electrode columns (210, 211) to create an electrode surface in which one top surface (222, 223) of each electrode column (210, 211) in the pattern of electrode columns is exposed; Forming a layer of programmable resistive material (230) on the electrode surface; Forming a layer of top
electrode material (231) over the layer of programmable resistive material (230); and Patterns of the layer of programmable resistive material (230) and the layer of top
electrode material (231).