Three-dimensional memory device containing through-array contact via structures between dielectric barrier walls and methods of making the same

A method for forming a three-dimensional memory device, comprising:

• forming an alternating stack of insulating layers and sacrificial material layers over a substrate, wherein the sacrificial material layers comprise a dielectric material;
• forming a dielectric material portion adjacent to the alternating stack and over the substrate;
• forming memory stack structures through the alternating stack;
• forming backside trenches and a moat trench through the alternating stack, wherein the moat trench has a continuous outer periphery and a continuous inner periphery, portions of the insulating layers surrounded by the moat trench constitute insulating plates, portions of the sacrificial material layers surrounded by the moat trench constitute dielectric spacer plates, and a vertically alternating sequence of the insulating plates and the dielectric spacer plates is provided surrounded by the moat trench;
• replacing portions of the sacrificial material layers outside the moat trench with electrically conductive layers without replacing the vertically alternating sequence of the insulating plates and the dielectric spacer plates;
• and
• simultaneously forming a first through-memory-level interconnection via structure extending through the vertically alternating sequence surrounded by the moat trench and a second through-memory-level interconnection via structure extending through the dielectric material portion in a peripheral region located between a horizontal plane including a bottom surface of the bottommost layer of the alternating stack of insulating layers and the electrically conductive layers and a horizontal plane including the top surface of the topmost layer of the alternating stack.