Abstract: A method includes forming a stack of alternating insulating layers and sacrificial layers over a substrate; forming a trench through the stack to uncover the substrate to expose lateral sides of the insulating layers and the sacrificial layers, the trench extending from a core area to a stair step area of the stack; forming a liner to cover the exposed lateral sides; removing the liner in the trenches within a first area of the core area and the stair step area to expose the lateral sides of the sacrificial layers of the stack within the first area; removing the sacrificial layers within the first area; removing the liner in the trenches within a second area of the core area and the stair step area to expose the lateral sides of the sacrificial layers of the stack within the second area; and removing the sacrificial layers within the second area.

Abstract: A method for manufacturing a three-dimensional storage includes: providing a substrate; forming a first connecting layer and a first sacrificial layer; etching part of the first sacrificial layer to form first grooves and second grooves; forming first connecting structures in the first grooves and second connecting structures in the second grooves; forming a second connecting layer on the first sacrificial layer, the second connecting layer filling up the first and second grooves; forming a stacked structure on a surface of the second connecting layer; forming a channel structure and a gate line slit penetrating the stacked structure and extending to the first sacrificial layer; removing the first sacrificial layer and a part of the channel structure corresponding to the first sacrificial layer by the gate line slit to form an opening region; and forming an epitaxial structure layer in the opening region through the gate line slit.

Abstract: Methods for forming channel structures in 3D memory devices are disclosed. In one example, a memory film and a sacrificial layer are subsequently formed along a sidewall and a bottom of a channel hole. A protective structure covering a portion of the sacrificial layer along the sidewall of the channel hole is formed. A portion of the sacrificial layer at the bottom of the channel hole that is not covered by the protective structure is selectively removed. A portion of the memory film at the bottom of the channel hole that is not covered by a remainder of the sacrificial layer is selectively removed.

Abstract: Methods for forming channel structures in 3D memory devices are disclosed. In one example, a memory film and a sacrificial layer are subsequently formed along a sidewall and a bottom of a channel hole. A protective structure covering a portion of the sacrificial layer along the sidewall of the channel hole is formed. A portion of the sacrificial layer at the bottom of the channel hole that is not covered by the protective structure is wet etched. A portion of the memory film at the bottom of the channel hole that is not covered by a remainder of the sacrificial layer is wet etched.

Abstract: Methods for forming channel structures in 3D memory devices are disclosed. In one example, a memory film and a sacrificial layer are subsequently formed along a sidewall and a bottom of a channel hole. A protective structure covering a portion of the sacrificial layer along the sidewall of the channel hole is formed. A portion of the sacrificial layer at the bottom of the channel hole that is not covered by the protective structure is selectively removed. A portion of the memory film at the bottom of the channel hole that is not covered by a remainder of the sacrificial layer is selectively removed.