Microelectronic devices with staircased stadiums and both through-step and to-step contacts, and related systems and methods

A microelectronic device, comprising:

• a stack structure comprising a vertically alternating sequence of insulative structures and conductive structures arranged in tiers;
• a series of stadiums within the stack structure, each of at least some of the stadiums comprising at least one staircase defined in a group of the tiers, the group of the tiers comprising:
• treaded tiers, the conductive structures of which provide treads of steps of the at least one staircase;
• and
• covered tiers, the conductive structures of which are each directly vertically below one of the treaded tiers;
• at least one conductive contact structure extending to one of the conductive structures providing one of the treads;
• at least one other conductive contact structure extending through one of the treaded tiers to one of the conductive structures of the covered tiers;
• and
• a dielectric contact liner spacing the at least one other conductive contact structure from the one of the conductive structures providing the one of the treads through which the at least one other conductive contact structure extends,
• the one of the conductive structures defining a lateral recess adjacent the at least one other conductive contact structure, the dielectric contact liner horizontally extending at an elevation of the one of the conductive structures to at least partially fill the lateral recess.

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

• forming a tiered stack over a base structure, the tiered stack comprising a vertically alternating sequence of insulative structures and other structures arranged in tiers;
• removing portions of the tiered stack to form a stadium within the tiered stack, the stadium comprising at least one staircase comprising steps at ends of some of the tiers of the tiered stack, the steps each comprising a tread provided by an upper surface portion of one of the other structures of the some of the tiers of the tiered stack;
• and
• forming conductive structures in place of the other structures so that each of the steps is provided by an upper surface portion of one of the conductive structures;
• forming openings in the conductive structures that provide the steps;
• for individuals of the steps:
• laterally recessing the one of the conductive structures providing the individual step to form a lateral recess defined by the one of the conductive structures;
• forming a dielectric material in the lateral recesses to form a dielectric contact liner;
• forming conductive contact structures extending to the individual step, comprising:
• forming a first conductive contact structure in physical contact with and terminating at the tread of the individual step;
• and
• forming a second conductive contact structure extending through the individual step adjacent the lateral recess, the dielectric contact liner spacing the second conductive contact structure from the tread of the individual step, the dielectric contact liner laterally protruding at an elevation of the one of the conductive structures providing the individual step to at least partially fill the lateral recess.

An electronic system, comprising:

• a microelectronic device comprising:
• a tiered stack comprising a vertically alternating sequence of insulative structures and conductive structures arranged in tiers;
• a stadium within the tiered stack and comprising a staircase comprising steps at ends of some of the tiers, the steps each comprising a tread provided by an upper surface portion of one of the conductive structures of the some of the tiers, the steps individually having a riser height of at least two of the tiers;
• and
• conductive contact structures extending to one of the steps of the stadium and comprising:
• a first conductive contact structure terminating at the tread of the one of the steps;
• and
• a second conductive contact structure extending through the tread of the one of the steps;
• a dielectric contact liner spacing the second conductive contact structure from the tread of the one of the steps,
• for individuals of the steps, the one of the conductive structures of the some of the tiers defines a lateral recess adjacent the second conductive contact structure, the dielectric contact liner laterally protruding at an elevation of the one of the conductive structures to at least partially fill the lateral recess;
• at least one processor in operable communication with the microelectronic device;
• and
• at least one peripheral device in operable communication with the at least one processor.