Three-dimensional memory device and method for forming the same

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

• a doped semiconductor layer;
• a stack structure comprising interleaved conductive layers and dielectric layers formed on the doped semiconductor layer, the conductive layers comprising a source select gate line, and a plurality of word lines;
• and
• a channel structure comprising a channel contact formed at a bottom region of the channel structure, the channel structure extending through the stack structure along a first direction and in contact with the doped semiconductor layer,
• wherein the source select gate line comprises a first dielectric layer in direct contact with the channel contact of the channel structure, and a first polysilicon layer in contact with the first dielectric layer.

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

• a doped semiconductor layer;
• a stack structure comprising interleaved conductive layers and dielectric layers formed over the doped semiconductor layer, the conductive layers comprising a plurality of word lines and a drain select gate line;
• and
• a channel structure comprising a semiconductor channel and a memory film over the semiconductor channel, and extending through the stack structure along a first direction to be in contact with the doped semiconductor layer,
• wherein:
• the drain select gate line extends in a second direction perpendicular to the first direction and extends through a first portion of the memory film to be in direct contact with the semiconductor channel;
• and
• one word line of the plurality of word lines extends in the second direction and is in contact with a second portion of the memory film.