Microelectronic devices including pseudo gate-all-around memory cell structures, and related memory devices and electronic systems

A microelectronic device, comprising:

• a stack structure comprising tiers each including conductive material vertically neighboring insulative material, the stack structure divided into blocks separated from one another in a first direction and horizontally extending in parallel in a second direction substantially orthogonal to the first direction, at least one of the blocks comprising:
• first filled slots vertically extending completely through the tiers of the stack structure and individually defined by two sidewalls of the stack structure horizontally extending in the first direction;
• and
• vertical memory string structures positioned at and around outer horizontal boundaries of the first filled slots, the vertical memory string structures comprising:
• memory cell material vertically extending completely through the tiers of the stack structure, the memory cell material comprising:
• semiconductor material;
• and
• a multi-material stack substantially continuously extending across and surrounding multiple outer horizontal boundaries of the semiconductor material, the multi-material stack comprising barrier oxide material, storage nitride material, and tunnel oxide material.

A memory device, comprising:

• a stack structure comprising blocks separated from one another in a first direction and horizontally extending in parallel in a second direction orthogonal to the first direction, the stack structure including tiers, each comprising conductive material and insulative material vertically neighboring the conductive material, the blocks individually comprising:
• first filled slots vertically extending through the tiers and comprising memory string structures vertically extending through the tiers and individually comprising:
• semiconductor material surrounded by the conductive material of the tiers of the stack structure;
• dielectric oxide material horizontally interposed between each of the three outer horizontal boundaries of semiconductive material and the conductive material of the tiers of the stack structure;
• dielectric nitride material horizontally interposed between the dielectric oxide material and the conductive material of the tiers of the stack structure;
• and
• additional dielectric oxide material horizontally interposed between the dielectric nitride material and the conductive material of the tiers of the stack structure;
• and
• dielectric-filled trenches vertically extending completely through the stack structure and horizontally alternating with the blocks in the first direction.