Memory arrays and methods used in forming a memory array comprising strings of memory cells and operative through-array-vias

A memory array comprising:

• a vertical stack comprising alternating insulative tiers and conductive tiers, the conductive tiers comprising gate regions of individual memory cells, the gate regions individually comprising part of a conductive line in individual of the conductive tiers;
• operative channel-material strings extending through the insulative tiers and the conductive tiers within a memory plane;
• the individual memory cells within the memory plane comprising a memory structure laterally between individual of the gate regions and channel material of the operative channel-material strings;
• and
• the vertical stack comprising a through-array-via (TAV) region comprising multiple operative TAVs and multiple dummy TAVs, the TAV region being one outside of the memory plane at an edge of the memory plane, the dummy TAVs being devoid of any conductive material and being devoid of any channel material.

A memory array comprising:

• a vertical stack comprising alternating insulative tiers and conductive tiers, the conductive tiers comprising gate regions of individual memory cells, the gate regions individually comprising part of a conductive line in individual of the conductive tiers;
• operative channel-material strings extending through the insulative tiers and the conductive tiers within a memory plane;
• the individual memory cells within the memory plane comprising a memory structure laterally between individual of the gate regions and channel material of the operative channel-material strings;
• an operative stair-step structure outside of the memory plane and comprising the insulative tiers and the conductive tiers;
• and
• a landing region adjacent steps of the operative stair-step structure, the landing region comprising a through-array-via (TAV) region that is outside the memory plane and operative TAVs that extend through the insulative tiers and the conductive tiers, the landing region further comprising dummy TAVs extending through the insulative tiers and the conductive tiers, the dummy TAVs being devoid of any conductive material and being devoid of any channel material.