Memory arrays comprising strings of memory cells and methods used in forming a memory array comprising strings of memory cells

Abstract

A memory array comprising strings of memory cells comprises laterally-spaced memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers directly above a conductor tier. Strings of memory cells comprise channel-material strings that extend through the insulative tiers and the conductive tiers. The channel-material strings directly electrically couple to conductor material of the conductor tier. A through-array-via (TAV) region comprises TAVs that individually extend through a lowest of the conductive tiers. Insulative rings are in the lowest conductive tier in the TAV region. Individual of the insulative rings encircle individual of the TAVs. The insulative rings extend through the lowest conductive tier and into the conductor tier. Outer rings are in the lowest conductive tier that individually encircle one of the individual insulative rings that encircle the individual TAVs. Other embodiments, including method, are disclosed.