Three-dimensional memory device containing alternating stack of source layers and drain layers and vertical gate electrodes

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

• forming an alternating stack of doped semiconductor source layers and doped semiconductor drain layers over a substrate;
• forming memory openings vertically extending through the alternating stack;
• forming a memory film and a gate electrode in each memory opening, wherein the memory film and the gate electrode vertically extend through each of the doped semiconductor source layers and the doped semiconductor drain layers of the alternating stack;
• and
• forming a vertical stack of semiconductor channels on horizontal surfaces of a respective vertically neighboring pair of a doped semiconductor source layer of the doped semiconductor source layers and a doped semiconductor drain layer of the doped semiconductor drain layers prior to, or after, formation of the memory film and the gate electrode, wherein each vertical stack of semiconductor channels laterally surrounds the respective memory film and the respective gate electrode.