Microelectronic devices including slot structures, and related memory devices, electronic systems, and methods

A microelectronic device comprises a stack structure, and slot structures vertically extending through the stack structure and dividing the stack structure into block structures. Each of the slot structures individually comprises an insulative liner material vertically extending through the slot structure and contacting sidewalls of the insulative levels and the conductive levels defining the slot structure, and grains of a material in contact with sidewalls of the insulative liner material. The grains of the material comprise first grains spanning an entire width between the sidewalls of the insulative liner material. Related memory devices, electronic systems, and methods are also described.