Microelectronic devices including tiered stacks including conductive structures isolated by slot structures, and related electronic systems and methods

A method of forming a microelectronic device, the method comprising:

• forming a first stack structure comprising alternating levels of insulative structures and other insulative structures;
• forming strings of memory cells comprising at least a dielectric material and a channel material vertically extending through the first stack structure;
• forming a second stack structure comprising alternating levels of additional insulative structures and additional other insulative structures vertically overlying the first stack structure;
• forming first pillars extending through the second stack structure and vertically overlying first strings of memory cells of the strings of memory cells, a center of each of the first pillars horizontally offset from a center of a corresponding string of memory cells;
• forming second pillars extending through the second stack structure and vertically overlying second strings of the strings of memory cells, a center of the each of the second pillars substantially horizontally aligned with a center of a corresponding string of memory cells;
• forming a slot structure horizontally neighboring the first pillars, the slot structure comprising a horizontal dimension greater than a horizontal distance between one of the first strings of memory cells and one of the second strings of memory cells;
• and
• replacing the other insulative structures and the additional other insulative structures through the slot structure to form respective conductive structures and additional conductive structures.

A microelectronic device, comprising:

• strings of memory cells extending through a first stack structure comprising tiers of alternating conductive structures and insulative structures, the strings of memory cells comprising at least a dielectric material and a channel material vertically extending through the first stack structure;
• a second stack structure vertically overlying the first stack structure;
• a first pillar extending through the second stack structure and vertically overlying a first string of memory cells of the strings of memory cells, a center of the first pillar horizontally offset from a center of the first string of memory cells of the strings of memory cells;
• a second pillar extending through the second stack structure and vertically overlying a second of the strings of memory cells, a center of the second pillar horizontally aligned with a center of the second of the strings of memory;
• and
• a slot structure horizontally neighboring the first pillar, the slot structure comprising a horizontal dimension greater than a horizontal distance between the first of the strings of memory cells and the second of the strings of memory cells.

An electronic system, comprising:

• an input device;
• an output device;
• a processor device operably coupled to the input device and the output device;
• and
• a memory device operably coupled to the processor device and comprising at least one microelectronic device structure, the at least one microelectronic device structure comprising:
• strings of memory cells extending through a first stack structure comprising alternating levels of insulative structures and conductive structures;
• a second stack structure vertically overlying the first stack structure comprising alternating levels of additional insulative structures and additional conductive structures;
• a first pillar extending through the second stack structure and vertically overlying a first of the strings of memory cells, a center of the first pillar horizontally offset from a center of the first of the strings of memory cells;
• a second pillar extending through the second stack structure and vertically overlying a second of the strings of memory cells, a center of the second pillar horizontally aligned with a center of the second of the strings of memory cells;
• a channel region extending through the first stack structure and the strings of memory cells, the channel region having a greater thickness between the first stack structure and the second stack structure than at other portions of the channel region;
• and
• a slot structure horizontally neighboring the first pillar, the slot structure comprising a horizontal dimension greater than a horizontal distance between the first of the strings of memory cells and the second of the strings of memory cells.