Semiconductor dies including low and high workfunction semiconductor devices
View Patent ↗A method of making a semiconductor die includes forming, over a substrate, a stack including insulating layers and sacrificial layers alternatively on top of each other; replacing a portion of first sacrificial layers located in a first portion of the stack to form first gate layers; forming first channel layers extending in a first direction in the first portion; forming first memory layers extending in the first direction in the first portion; replacing a portion of second sacrificial layers located in a second portion of the stack to form second gate layers; forming second channel layers extending in the first direction in the second portion; and forming second memory layers extending in the first direction in the second portion.
1. A method of making a semiconductor die, comprising:
providing a substrate;
forming a stack comprising a plurality of insulating layers and a plurality of sacrificial layers alternatively stacked on top of each other;
replacing at least a portion of first sacrificial layers of the plurality of sacrificial layers located in a stack first portion of the stack to form first gate layers;
forming first channel layers extending in a first direction in the stack first portion;
forming first memory layers extending in the first direction in the stack first portion;
subsequently, replacing at least a portion of second sacrificial layers of the plurality of sacrificial layers located in a stack second portion of the stack to form second gate layers;
forming second channel layers extending in the first direction in the stack second portion;
forming second memory layers extending in the first direction in the stack second portion; and
forming:
first sources and first drains spaced apart from a corresponding first source in the first direction such that a corresponding first channel layer is disposed on radially outer surface of the first sources and the first drains in the first direction to form a first set of semiconductor devices, and
second sources and second drains spaced apart from a corresponding second source in the first direction such that a corresponding second channel layer is disposed on radially outer surface of the second sources and the second drains in the first direction to form a second set of semiconductor devices,
wherein each of the first set of semiconductor devices has a first workfunction different from a second workfunction of each of the second set of semiconductor devices.
2. The method of claim 1 , wherein:
the first gate layers included in each of the first set of semiconductor devices are formed of a first material to cause the each of the first set of semiconductor devices to have the first workfunction; and
the second gate layer included in each of the second set of semiconductor devices are formed of a second material different from the first material to cause each of the second set of semiconductor devices to have the second workfunction.
3. The method of claim 1 , wherein:
each of the first gate layers is formed of a n-type material; and
the second set of semiconductor devices is formed to include a barrier layer interposed between the memory layer and the second gate layer included in each of the second set of semiconductor devices.
4. The method of claim 3 , wherein a first thickness of the first gate layer included in each of the first set of semiconductor devices is approximately equal to a sum of a second thickness of the second gate layer included in each of the second set of semiconductor devices and a thickness of the barrier layer included in each of the second set of semiconductor devices.
5. The method of claim 1 , wherein:
each of the at least one gate layer included in the first set and the second set of semiconductor devices is formed of a n-type material;
each of the first set of semiconductor devices is formed to include a first barrier layer interposed between the memory layer and the at least one gate layer included in each of the first set of semiconductor devices, the first barrier layer having a first barrier thickness; and
each of the second set of semiconductor devices is formed to include a second barrier layer interposed between the memory layer and the at least one gate layer included in each of the second set of semiconductor devices, the second barrier layer having a second barrier thickness greater than the first barrier thickness.
6. The method of claim 1 , wherein:
each of the at least one gate layer included in the first set and the second set of semiconductor devices is formed of a p-type material;
each of the first set of semiconductor devices is formed to include a first barrier layer interposed between the memory layer and the at least one gate layer included in each of the first set of semiconductor devices, the first barrier layer having a first barrier thickness; and
each of the second set of semiconductor devices is formed to include a second barrier layer interposed between the memory layer and the at least one gate layer included in each of the second set of semiconductor devices, the second barrier layer having a second barrier thickness that is less than the first barrier thickness.
7. The method of claim 6 , wherein:
a first sum of a thickness of the at least one gate layer included in each of the first set of semiconductor devices and the first barrier thickness is approximately equal to a second sum of a thickness of the at least one gate layer included in each of the second set of semiconductor devices and the second barrier thickness.
8. The method of claim 1 , wherein:
a first channel thickness of the first channel layer included in each of the first set of semiconductor devices is different from a second channel thickness of the second channel layer included in each of the second set of semiconductor devices.
9. The method of claim 1 , wherein:
a first channel material of the first channel layer included in each of the first set of semiconductor devices is different from a second channel material of the second channel layer included in each of the second set of semiconductor devices.
10. The method of claim 1 , wherein the at least one first gate layer included in each of the first set of semiconductor devices is formed of a first material that is different from a second material of the at least one second gate layer included in each of the second set of semiconductor devices.
11. The method of claim 1 , wherein:
the first set of semiconductor devices is disposed adjacent to the second set of semiconductor devices in at least a first direction, a second direction perpendicular to the first direction, or the first direction and the second direction; and
an array isolation layer is interposed between the first set and the second set of semiconductor devices.
12. A method of making a semiconductor die, comprising:
providing a semiconductor die;
forming a first set of semiconductor devices disposed at a first location of the semiconductor die; and
forming a second set of semiconductor devices disposed at a second location of the semiconductor die different from the first location;
wherein forming each of the first set of semiconductor devices comprises:
forming a first source;
forming a first drain spaced apart from the first source in a first direction by a first inner spacer;
forming a first channel layer disposed radially outwards of radially outer surfaces of the inner first spacer, the first source and the first drain in a second direction perpendicular to the first direction and extending in the first direction; and
forming a first memory layer disposed on a radially outer surface of the forming channel layer in the second direction and extending in the first direction.
13. The method of claim 12 , wherein forming each of the second set of semiconductor devices comprises:
forming a second source;
forming a second drain spaced apart from the second source in the first direction by a second inner spacer;
forming a second channel layer disposed radially outwards of radially outer surfaces of the second inner spacer, the second source and the second drain in the second direction perpendicular to the first direction and extending in the first direction; and
forming a second memory layer disposed on a radially outer surface of the second channel layer in the second direction and extending in the first direction.
14. The method of claim 13 , further comprising:
forming a first global source line and a first global drain line on a top surface of the first set of semiconductor devices.
15. The method of claim 14 , further comprising:
connecting the first global source line to the first source of each of the first set of semiconductor devices; and
connecting the first global drain line to the first drain of each of the first set of semiconductor devices.
16. The method of claim 13 , further comprising:
forming a second global source line and a second global drain line on a top surface of the second set of semiconductor devices.
17. The method of claim 16 , further comprising:
connecting the second global source line to the second source of each of the second set of semiconductor devices; and
connecting the second global drain line to the second drain of each of the second set of semiconductor devices.
18. A method of making a semiconductor die, comprising:
forming a stack over a substrate, the stack comprising a plurality of insulating layers and a plurality of sacrificial layers alternatively stacked on top of each other;
replacing at least a portion of first sacrificial layers of the plurality of sacrificial layers located in a first portion of the stack to form first gate layers;
forming first channel layers extending in a first direction in the first portion;
forming first memory layers extending in the first direction in the first portion;
subsequently, replacing at least a portion of second sacrificial layers of the plurality of sacrificial layers located in a second portion of the stack to form second gate layers;
forming second channel layers extending in the first direction in the second portion; and
forming second memory layers extending in the first direction in the second portion.
19. The method of claim 18 , further comprising:
forming first sources and first drains spaced apart from a corresponding first source in the first direction such that a corresponding first channel layer is disposed on radially outer surface of the first sources and the first drains in the first direction to form a first set of semiconductor devices.
20. The method of claim 19 , further comprising:
forming second sources and second drains spaced apart from a corresponding second source in the first direction such that a corresponding second channel layer is disposed on radially outer surface of the second sources and the second drains in the first direction to form a second set of semiconductor devices, wherein each of the first set of semiconductor devices has a first workfunction different from a second workfunction of each of the second set of semiconductor devices.