Methods for forming channel structures with reduced sidewall damage in three-dimensional memory devices
AssigneeYangtze Memory Technologies Co., Ltd.
InventorsXiaofen Zheng, Hongbin Zhu, Lixun Gu, Hanwei Yi
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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.
Claims20
A method for forming a three-dimensional (3D) memory device, comprising:
- subsequently forming a memory film and a sacrificial layer along a sidewall and a bottom of a channel hole;
- forming a protective structure covering a portion of the sacrificial layer along the sidewall of the channel hole;
- selectively removing a portion of the sacrificial layer at the bottom of the channel hole that is not covered by the protective structure;
- and
- selectively removing a portion of the memory film at the bottom of the channel hole that is not covered by a remainder of the sacrificial layer, comprising using the remainder of the sacrificial layer as a mask, removing a portion of a tunnel layer of the memory film at the bottom of the channel hole to expose a storage layer of the memory film.
A method for forming a three-dimensional (3D) memory device, comprising:
- subsequently forming a memory film and a sacrificial layer along a sidewall and a bottom of a channel hole;
- removing a portion of the sacrificial layer at the bottom of the channel hole to expose a first portion of the memory film at the bottom of the channel hole;
- and
- wet etching the first portion of the memory film at the bottom of the channel hole by using a remainder of the sacrificial layer as an etching mask to expose a semiconductor plug, the remainder of the sacrificial layer comprising a first portion along the sidewall of the channel hole and a second portion remaining at the bottom of the channel hole,
- wherein after the first portion of the memory film is removed, a second portion of the memory film at the bottom of the channel hole remains on the semiconductor plug.
A method for forming a three-dimensional (3D) memory device, comprising:
- subsequently forming a memory film and a sacrificial layer along a sidewall and a bottom of a channel hole, the memory film comprising a tunnel layer, a storage layer, and a block layer;
- forming a protective structure covering a portion of the sacrificial layer along the sidewall of the channel hole;
- selectively removing a portion of the sacrificial layer at the bottom of the channel hole that is not covered by the protective structure, comprising etching the portion of the sacrificial layer by using the tunnel layer as an etch stop layer, a remainder of the sacrificial layer comprising a first portion along the sidewall of the channel hole and a second portion remaining at the bottom of the channel hole;
- and
- selectively removing a portion of the memory film at the bottom of the channel hole that is not covered by a remainder of the sacrificial layer, wherein:
- the protective structure and at least one of the block layer, the storage layer, or the tunnel layer comprise a same material;
- and
- the method comprises simultaneously etching the protective structure and the at least one of the block layer, the storage layer, or the tunnel layer comprising the same material.
Dependencies are inferred from the claim text.