Electronic devices comprising an oxide fill region, and related electronic systems and methods

An electronic device, comprising:

• an oxide fill region in a source stack comprising one or more conductive materials;
• a source contact adjacent to the source stack;
• a doped semiconductive material adjacent to the source contact;
• tiers of alternating conductive materials and dielectric materials adjacent to the doped semiconductive material;
• pillars extending through the tiers of alternating conductive materials and dielectric materials and into the source stack;
• and
• a fill material laterally adjacent to the pillars and extending through the tiers of alternating conductive materials and dielectric materials and the doped semiconductive material, the fill material vertically adjacent to the source contact and exhibiting a smaller width in a lateral direction than a width in the lateral direction of the oxide fill region.

An electronic system, comprising:

• an input device;
• an output device;
• a processor device operably coupled to the input device and to the output device;
• and
• one or more memory devices operably coupled to the processor device, the one or more memory devices comprising:
• a source contact adjacent to a source stack;
• an oxide fill region within an upper portion of the source stack;
• a semiconductive material adjacent to the source contact;
• tiers of alternating conductive materials and dielectric materials adjacent to the semiconductive material;
• memory pillars extending through the tiers of alternating conductive materials and dielectric materials, the semiconductive material, the source contact, and partially into the source stack;
• and
• a fill material extending through the tiers of alternating conductive materials and dielectric materials and overlying the oxide fill region and a portion of the source contact.

A method of forming an electronic device, the method comprising:

• forming a source contact sacrificial structure adjacent to a source stack;
• forming an oxide fill region adjacent to the source contact sacrificial structure;
• forming a slit sacrificial structure vertically neighboring the oxide fill region;
• forming a doped semiconductive material adjacent to the source contact sacrificial structure;
• forming tiers adjacent to the doped semiconductive material, the tiers comprising alternating dielectric materials and nitride materials;
• forming pillars through the tiers, the doped semiconductive material, the source contact sacrificial structure, and the source stack, the pillars including a channel, a charge blocking material, and a charge trap material;
• forming a slit vertically adjacent to the slit sacrificial structure through the tiers to expose the source contact sacrificial structure;
• removing at least a portion of the slit sacrificial structure and the source contact sacrificial structure to form a source contact opening;
• forming a source contact in the source contact opening and in a portion of the slit;
• removing at least a portion of the source contact in the slit;
• forming a liner on an upper surface of the source contact;
• replacing the nitride materials in the tiers with conductive materials;
• and
• forming a fill material in the slit, a portion of the fill material neighboring the oxide fill region.