A method of making a memory device includes forming a first conductive electrode (28), forming an insulating structure (13) over the first conductive electrode, forming a resistivity switching element (14) on a sidewall of the insulating structure, forming a second conductive electrode (26) over the resistivity switching element, and forming a steering element (22) in series with the resistivity switching element between the first conductive electrode and the second conductive electrode, wherein a height of the resistivity switching element in a first direction from the first conductive electrode to the second conductive electrode is greater than a thickness of the resistivity switching element in second direction perpendicular to the first direction.