Memory circuitry and method used in forming memory circuitry

Abstract

A method used in forming memory circuitry comprises forming a stack comprising vertically-alternating first tiers and second tiers. The stack extends from a memory-array region into a stair-step region. The stack in the stair-step region comprises a cavity comprising a flight of stairs in a vertical cross-section along a first direction. The first tiers are conductive and the second tiers are insulative in a finished-circuitry construction. An insulating lining is formed in the cavity atop treads of the stairs and laterally-over sidewalls of the cavity that are along the first direction. Individual of the treads comprise conducting material of one of the conductive tiers in the finished-circuitry construction. The insulating lining is thicker in a bottom part of the cavity than over the sidewalls of the cavity that are above the bottom part. Insulative material is formed in the cavity directly above the insulating lining. Conductive vias are formed through the insulative material and the insulating lining. Individual of the conductive vias are directly above and directly against the conducting material of the tread of individual of the stairs. Other embodiments, including structure, are disclosed.