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

A memory device, comprising:

• a stack structure comprising tiers of alternating conductive structures and insulative structures;
• another stack structure vertically overlying the stack structure and comprising other conductive structures and other insulative structures arranged in other tiers, each of the other tiers comprising one of the other conductive structures and one of the other insulative structures, the other conductive structures exhibiting a larger grain size than the conductive structures;
• pillars extending through the stack structure and the another stack structure, each pillar comprising:
• a channel material extending through the stack structure and the another stack structure;
• and
• a string of memory cells comprising the channel material and at least one dielectric material within the stack structure;
• and
• select gate slots extending through the another stack structure.

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

• forming a first stack structure comprising alternating conductive structures and insulative structures,
• forming the first stack structure comprising:
• forming memory strings comprising a channel material and at least one dielectric material extending through the first stack structure;
• and
• forming a second stack structure comprising alternating other conductive structures and other insulative structures vertically over the first stack structure, forming the second stack structure comprising:
• forming the other conductive structures by physical vapor deposition;
• forming openings in the second stack structure vertically overlying the memory strings;
• and
• forming a channel material in electrical communication with the channel material of the memory strings.

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, the at least one microelectronic device 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 and comprising alternating levels of other insulative structures and other conductive structures, the other conductive structures exhibiting a greater conductivity than the conductive structures of the first stack structure;
• and
• a channel material extending through the second stack structure and in electrical communication with a channel material of the strings of memory cells.