Three-dimensional memory devices with stabilization structures between memory blocks and methods for forming the same

A three-dimensional (3D) memory device, comprising:

• a plurality of memory blocks arranged in a bit line direction in a plan view, each of the memory blocks comprising a plurality of memory fingers arranged in the bit line direction and at least one slit structure having an “H” cut each between adjacent ones of the memory fingers in the bit line direction, each of the memory fingers comprising an array of channel structures;
• a semiconductor stack including a first semiconductor layer and a second semiconductor layer, wherein the channel structures each extending vertically through the first semiconductor layer into the second semiconductor layer;
• and
• at least one stabilization structure each extending laterally in a word line direction between adjacent ones of the memory blocks in the bit line direction, wherein the stabilization structure comprises a dielectric stack comprising vertically interleaved first dielectric layers and second dielectric layers, and a residual stop layer coplanar with the first semiconductor layer and in contact with the second semiconductor layer.

A method for forming a three-dimensional (3D) memory device, comprising:

• forming a stop layer on a substrate;
• forming a sacrificial layer on the stop layer;
• forming a dielectric stack comprising vertically interleaved first dielectric layers and second dielectric layers on the sacrificial layer;
• forming a plurality of channel structures each extending vertically through the dielectric stack and the sacrificial layer;
• forming at least one opening extending laterally in a word line direction and vertically through the dielectric stack to expose the sacrificial layer;
• replacing, through the at least one opening, part of the sacrificial layer and the stop layer with a semiconductor layer;
• and
• replacing, through the at least one opening, part of the dielectric stack with a memory stack by replacing parts of the second dielectric layers with conductive layers to form a stabilization structure comprising:
• a remainder of the stop layer in contact with the substrate,
• a remainder of the sacrificial layer on the remainder of the stop layer, and
• a remainder of the dielectric stack that extends laterally in the word line direction.