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 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 with conductor material of the conductor tier by conducting material that is in a lowest of the conductive tiers and that is directly against multiple of the channel-material strings. A through-array-via (TAV) region comprises TAVs that individually extend through the lowest conductive tier and into the conductor tier. Individual of the TAVs in the lowest conductive tier comprise a conductive core having an annulus circumferentially there-about. The annulus has dopant therein at a total dopant concentration of 0.01 to 30 atomic percent. Insulative material in the lowest conductive tier is circumferentially about the annulus and between immediately-adjacent of the TAVs. Other embodiments, including method, are disclosed.