Three-dimensional memory device containing contact via structure extending through source contact layer and dielectric spacer assembly
A dielectric spacer assembly including an annular dielectric isolation structure is formed through in-process source-level material layers. An alternating stack of insulating layers and spacer material layers is formed over the in-process source-level material layers. A contact via cavity is formed through the dielectric spacer assembly, and is filled within a dielectric spacer and a sacrificial via fill structure. The dielectric spacer assembly protects the dielectric spacer during replacement of a source-level sacrificial layer with a source contact layer. The sacrificial via fill structure is subsequently replaced with a through-memory-level contact via structure.
1. A three-dimensional memory device, comprising:
source-level material layers located over a substrate and comprising a lower source-level material layer, an upper source-level material layer and a source contact layer located therebetween;
an alternating stack of insulating layers and electrically conductive layers located over the source-level material layers;
a memory stack structure extending through the alternating stack and comprising a memory film and a vertical semiconductor channel, wherein a sidewall of the vertical semiconductor channel contacts the source contact layer; and
a through-memory-level contact via structure vertically extending through the alternating stack and the source-level material layers and is laterally surrounded by a dielectric spacer;
wherein the upper source-level material layer contacts the dielectric spacer, and the source contact layer is laterally spaced apart from, and does not contact, the dielectric spacer.
2. The three-dimensional memory device of claim 1 , further comprising an annular dielectric isolation structure located within an opening in the source contact layer and between the upper source-level material layer and the lower source-level material layer, and laterally surrounding the dielectric spacer.
3. The three-dimensional memory device of claim 2 , further comprising a dielectric material block contacting a portion of a bottom surface of the lower source-level material layer, wherein the through-memory-level contact via structure and the dielectric spacer vertically extend through an opening through the dielectric material block.
4. The three-dimensional memory device of claim 3 , further comprising an upper annular dielectric liner contacting a top surface of the annular dielectric isolation structure and including an opening that contacts a periphery of an outer sidewall of the dielectric spacer.
5. The three-dimensional memory device of claim 4 , further comprising a source-level semiconductor plate laterally surrounding the upper annular dielectric liner, contacting a bottom surface of the upper annular dielectric liner, and overlying the dielectric material block.
6. The three-dimensional memory device of claim 4 , wherein an annular bottom surface of the annular dielectric isolation structure contacts a top surface of the dielectric material block.
7. The three-dimensional memory device of claim 6 , further comprising a lower annular dielectric liner contacting an inner sidewall of the annular dielectric isolation structure, including an opening through which the through-memory-level contact via structure and the dielectric spacer vertically extend, and overlying, and vertically spaced from, the dielectric material block.
8. The three-dimensional memory device of claim 7 , further comprising a doped semiconductor plate located between the lower annular dielectric liner and the dielectric material block, laterally surrounding the through-memory-level contact via structure and the dielectric spacer, and laterally surrounded by the annular dielectric isolation structure.
9. The three-dimensional memory device of claim 4 , wherein an annular bottom surface of the annular dielectric isolation structure is located above, and is vertically spaced from, a top surface of the dielectric material block.
10. The three-dimensional memory device of claim 9 , further comprising a lower annular dielectric liner contacting a bottom surface of the annular dielectric isolation structure, including an opening through which the through-memory-level contact via structure and the dielectric spacer vertically extend, and overlying, and vertically spaced from, the dielectric material block.
11. The three-dimensional memory device of claim 10 , wherein the lower source-level material layer contacts a bottom surface of the lower annular dielectric liner and a top surface of the dielectric material block.
12. The three-dimensional memory device of claim 3 , wherein the dielectric material block is formed within a doped semiconductor material underlayer that laterally surrounds, and contacts, the dielectric material block.
13. The three-dimensional memory device of claim 2 , wherein:
the source contact layer is spaced apart from the dielectric spacer by a dielectric spacer assembly; and
the dielectric spacer assembly comprises:
a lower annular dielectric liner contacting a surface of the lower source-level material layer;
an upper annular dielectric liner contacting a bottom surface of the upper source-level material layer; and
the annular dielectric isolation structure contacting the lower annular dielectric liner and the upper dielectric liner.
14. The three-dimensional memory device of claim 1 , wherein:
the source-level material layers comprise doped semiconductor layers;
the source contact layer contacts the sidewall of the vertical semiconductor channel;
the three-dimensional memory device comprises a NAND memory device; and
the electrically conductive layers comprise word lines of the NAND memory device.