Abstract: Some embodiments include apparatuses and methods of forming the apparatuses. One of the apparatuses includes tiers located one over another; a first staircase structure formed in the tiers; a second staircase structure formed in the tiers adjacent the first staircase structure, respective portions of conductive materials in the tiers forming a part of the first and second staircase structure and a part of respective control gates associated with memory cells; a first trench structure formed in the tiers adjacent the first staircase structure and the second staircase structure, the first trench structure including length in a direction from the first staircase structure to the second staircase structure; and a second trench structure formed in the tiers adjacent the first trench structure, the second trench structure including a length in the direction from the first staircase structure to the second staircase structure.

Abstract: A method used in forming memory circuitry comprises forming a stack comprising vertically-alternating first tiers and second tiers, with the stack extending from a memory-array region into a stair-step region. The stair-step region comprises a flight of stairs in a first vertical cross-section along a first direction. Masking material is formed directly above the flight of stairs. A species is ion implanted into the masking material to form different-composition first and second regions that are directly above individual of the stairs along a second direction that is orthogonal to the first direction. One of the first and the second regions is removed selectively relative to the other of the first and the second regions.