Memory cell, wafer, semiconductor component with memory cell having insulation collars and method for fabricating an insulating collar for a memory cell
View Patent ↗The invention relates to a DRAM memory cell having a trench filled with conductive material connected to a selection transistor by a connection having a vertical insulation collar arranged perpendicularly to a layer sequence of the memory cell. The vertical insulation collar is connected to a lateral insulation collar of the trench. This lateral insulation collar essentially extends perpendicular to the vertical insulation collar or is arranged laterally with respect to the vertical insulation collar. It is thus possible to provide a memory cell, a wafer and a semiconductor component that have a high integration density and a sufficient dielectric strength, and that efficiently suppress parasitic transistors. A method for fabricating a lateral insulating collar for a memory cell is also described.
1. A memory cell, comprising:
a trench filled with a conductive material;
a selection transistor;
a connection connecting said conductive material to said selection transistor, said connection including a vertical insulation collar having a maximum thickness in a horizontal direction; and
a lateral insulation collar for said trench, said lateral insulation collar having a maximum height in a vertical directions said maximum thickness of said vertical insulation collar being less than said maximum height of said lateral insulation collar;
said vertical insulation collar connected to said lateral insulation collar; and
said lateral insulation cellar configured laterally with respect to said vertical insulation collar.
2. The memory cell according to claim 1 , wherein: said lateral insulation collar has a rectangular cross sectional area.
3. The memory cell according to claim 1 , wherein: said lateral insulation collar has a circular cross sectional area.
4. The memory cell according to claim 1 , wherein: said lateral insulation collar has a cross sectional area shaped as a quarter circle.
5. The memory cell according to claim 1 , wherein: said vertical insulation collar has a thickness of 3 to 5 nm.
6. The memory cell according to claim 1 , in combination with a parasitic transistor having an inversion layer near the memory cell, wherein:
said lateral insulation collar has a height chosen such that the inversion layer of the parasitic transistor can essentially be suppressed.
7. The memory cell according to claim 1 , wherein: said vertical insulation collar has a length chosen such that a voltage present at said vertical insulation collar is less than a breakdown voltage.
8. The memory cell according to claim 1 , wherein: said trench is a deep trench.
9. The memory cell according to claim 1 , wherein: said trench is a bottle trench.
10. The memory cell according to claim 1 , wherein: said selection transistor is a planar transistor.
11. The memory cell according to claim 1 , wherein: said selection transistor is a vertical transistor.
12. A memory cell, comprising:
a trench filled with a conductive material;
a selection transistor;
a connection connecting said conductive material to said selection transistor, said connection including a vertical insulation collar having a maximum thickness in a horizontal direction; and
a lateral insulation collar for said trench, said lateral insulation collar having a maximum height in a vertical direction, said maximum thickness of said vertical insulation collar being less than said maximum height of said lateral insulation collar;
said vertical insulation collar connected to said lateral insulation collar; and
said lateral insulation collar essentially extending perpendicular to said vertical insulation collar.
13. The memory cell according to claim 12 , wherein: said lateral insulation collar has a rectangular cross sectional area.
14. The memory cell according to claim 12 , wherein: said lateral insulation collar has a circular cross sectional area.
15. The memory cell according to claim 12 , wherein: maid lateral insulation collar has a cross sectional area shaped as a quarter circle.
16. The memory cell according to claim 12 , wherein: said vertical insulation collar has a thickness of 3 to 5 nm.
17. The memory cell according to claim 12 , in combination with p parasitic transistor having an inversion layer near the memory cell, wherein:
said lateral insulation collar has a height chosen such that the inversion layer of the parasitic transistor can essentially be suppressed.
18. The memory cell according to claim 12 , wherein: said vertical insulation collar has a length chosen such that a voltage present at said vertical insulation collar is less than a breakdown voltage.
19. The memory cell according to claim 12 , wherein: said trench is a deep trench.
20. The memory cell according to claim 12 , wherein: said trench is a bottle trench.
21. The memory cell according to claim 12 , wherein: said selection transistor is a planar transistor.
22. The memory cell according to claim 12 , wherein: said selection transistor is a vertical transistor.
23. A wafer, comprising at least one memory cell including:
a trench filled with a conductive material;
a selection transistor;
a connection connecting said conductive material to said selection transistor, said connection including a vertical insulation collar having a maximum thickness in a horizontal direction; and
a lateral insulation collar for said trench, said lateral insulation collar having a maximum height in a vertical direction, said maximum thickness of said vertical insulation collar being less than said maximum height of said lateral insulation collar;
said vertical insulation collar connected to said lateral insulation collar; and
said lateral insulation collar configured laterally with respect to said vertical insulation collar.
24. A semiconductor component, comprising at least one memory cell including:
a trench filled with a conductive material;
a selection transistor;
a connection connecting said conductive material to said selection transistor, said connection including a vertical insulation collar having a maximum thickness in a horizontal direction; and
a lateral insulation collar for said trench, said lateral insulation collar having a maximum height in a vertical direction, said maximum thickness of said vertical insulation collar being less than said maximum height of said lateral insulation collar;
said vertical insulation collar connected to said lateral insulation collar; and
said lateral insulation collar configured laterally with respect to said vertical insulation collar.