Through array contact structure of three-dimensional memory device

A memory device, comprising:

• a first substrate with a peripheral circuit;
• a second substrate disposed on the first substrate;
• a first stack disposed on the second substrate comprises first dielectric layers and second dielectric layers arranged alternately in a vertical direction;
• and
• a second stack disposed on the second substrate comprises conductor layers and third dielectric layers arranged alternately in the vertical direction;
• a barrier structure extending vertically through the first stack and laterally separating the first stack from the second stack, wherein the barrier structure comprises two parallel first sub-barrier structures;
• a through array contact structure extending vertically through the first stack to the first substrate;
• and
• a slit structure extending through the second stack along a first lateral direction perpendicular to the vertical direction, and comprising a conductive structure.