Three-dimensional memory device including inverted memory stack structures and methods of making the same

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

• providing a first assembly comprising memory stack structures vertically extending through an alternating stack of insulating layers and electrically conductive layers over a carrier substrate, wherein each of the memory stack structures comprises a memory film and a vertical semiconductor channel;
• bonding the first assembly to a second assembly comprising a semiconductor substrate, field effect transistors located on the semiconductor substrate, and first metal interconnect structures embedded in first dielectric material layers;
• separating the carrier substrate from the alternating stack;
• forming an interconnection via cavity through the alternating stack;
• and
• forming a contact via structure in the interconnection via cavity;
• forming source-select-level channel portions at upper end regions of vertical semiconductor channels by performing a first ion implantation process prior to bonding the first assembly with the second assembly;
• forming drain-select-level channel portions at end regions of the vertical semiconductor channels that are distal from the semiconductor substrate by performing a second ion implantation process after bonding the first assembly with the second assembly;
• forming source regions at top ends of the memory stack structures prior to bonding the first assembly with the second assembly;
• forming drain regions at end regions of the memory stack structures that are distal from the semiconductor substrate after bonding the first assembly with the second assembly;
• and
• forming second metal interconnect structures on the drain regions.