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US 12,598,965 B2Granted
3D NAND memory device with isolation trenches and fabrication method thereof
AssigneeYangtze Memory Technologies Co., Ltd.
InventorsHuidan Hou, Lan Yao, Yanwei Shi
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Abstract
The present disclosure discloses a semiconductor device and a fabrication method thereof. In the method, firstly etching a substrate in a first device region to form at least one first trench and then etching the substrate in both first device region and second device region to form at least one first isolation trench at the positions corresponding to the at least one first trench and form at least one second isolation trench in the second device region. Herein a depth of the first isolation trench is larger than that of the second isolation trench.
Claims19
A method of fabricating a semiconductor device, comprising:
- providing a substrate having a first device region and a second device region;
- etching the substrate in the first device region to form a plurality of first trenches;
- forming first doped well regions in the substrate with each of the first doped well regions being located between two adjacent first trenches of the plurality of first trenches;
- after forming the first doped well regions, etching the substrate in both the first device region and the second device region to form at least one first isolation trench at positions corresponding to the plurality of first trenches and form at least one second isolation trench in the second device region;
- and
- forming second doped well regions in the substrate with each of the second doped well regions being located between every two neighboring second isolation trenches, a depth of the second doped well region in a vertical direction being less than the depth of the first doped well region in the vertical direction,
- wherein a depth of the first isolation trench in a vertical direction perpendicular to the substrate is larger than a depth of the second isolation trench in the vertical direction.
4 more elements
A method of fabricating a semiconductor device, comprising:
- performing a first removal operation on a substrate to form a first trench in a first device region of the substrate;
- forming a first doped well region in the first device region adjacent to the first trench, comprising:
- forming a first sacrificial layer on the substrate;
- performing a first implantation operation on portions of the substrate adjacent to the first trench;
- removing the first sacrificial layer;
- forming a second sacrificial layer on the substrate;
- performing a second implantation operation on portions of the substrate adjacent to the first trench;
- and
- removing the second sacrificial layer;
- after forming the first doped well region, performing a second removal operation on the substrate to deepen the first trench in the first device region and form a second trench in a second device region of the substrate;
- and
- forming a second doped well region in the second device region adjacent to the first trench.
9 more elements
A method of fabricating a semiconductor device, comprising:
- providing a substrate having a first device region and a second device region;
- etching the substrate in the first device region to form a plurality of first trenches;
- forming first doped well regions in the substrate with each of the first doped well regions being located between two adjacent first trenches of the plurality of first trenches, comprising:
- forming a first sacrificial layer on the substrate;
- performing a first ion implantation on portions of the substrate with each portion being located between two adjacent first trenches;
- removing the first sacrificial layer;
- forming a second sacrificial layer on the substrate at both the first device region and the second device region;
- performing a second ion implantation on the portions of the substrate with each portion being located between two adjacent first trenches, to form the first doped well regions being located between two adjacent first trenches;
- and
- removing the second sacrificial layer in the first device region;
- and
- after forming the first doped well regions, etching the substrate in both the first device region and the second device region to form at least one first isolation trench at positions corresponding to the plurality of first trenches and form at least one second isolation trench in the second device region,
- wherein a depth of the first isolation trench in a vertical direction perpendicular to the substrate is larger than a depth of the second isolation trench in the vertical direction.
10 more elements
Dependencies are inferred from the claim text.