Embodiments of structure and methods for forming a staircase structure of a memory device are disclosed. In an example, a memory device includes a memory array structure and a staircase structure. The staircase structure includes a plurality of stairs each has a first number of divisions at different depths along a first direction. The plurality of stairs extend along a second direction perpendicular to the first direction. Each of the first number of divisions of a respective stair includes a conductor portion on the top surface of the respective division and a second number of non-conductor portions under the conductor portion. The conductor portion and the non-conductor portions are insulated from one another by one or more dielectric layers.