Memory device and method for forming the same

A method for forming a memory device, comprising:

• providing an initial semiconductor structure, including a base substrate;
• a first stop layer formed on the base substrate;
• a first sacrificial layer formed on the first stop layer;
• a second stop layer disposed on the first sacrificial layer;
• a stack structure, disposed on the second stop layer;
• a plurality of channels formed through the stack structure and into the base substrate;
• and a gate-line trench, formed through the stack structure and exposing the first sacrificial layer;
• forming a protective layer on a bottom and sidewalls of the gate-line trench;
• removing a portion of the protective layer formed on the bottom of the gate-line trench;
• removing the first sacrificial layer to expose a portion of each of the plurality of channels and surfaces of the base substrate, using the protective layer as an etch mask;
• and
• forming an epitaxial layer on the exposed surfaces of the base substrate and the plurality of channels.