Trench capacitor and method for fabricating a trench capacitor
AssigneeInfineon Technologies AG
InventorMartin Schrems
Life of this patent
Estimating the term…
Abstract
A trench capacitor has an insulation collar that is formed non-conformally in the upper region of a trench in such a way that a layer thickness in an upper section of the insulation collar is greater than a layer thickness in a lower section of the insulation collar. This results in a trench capacitor having improved leakage current properties. A simplified and cost-effective method of fabricating a trench capacitor is also provided.
Claims46
A trench capacitor, comprising:
- a substrate having a trench formed therein, said trench having an upper region and a lower region;
- an insulation collar formed non-conformally in said upper region of said trench, said insulation collar having an upper section and a lower section, said insulation collar having a first layer thickness in said upper section and having a second layer thickness in said lower section, said first layer thickness being greater than said second layer thickness;
- a buried plate formed adjacent to said lower region of said trench as a first capacitor plate;
- a dielectric layer lining said lower region of said trench and said insulation collar as a capacitor dielectric;
- and
- a conductive filling material filled into said trench as a second capacitor plate.
A method for fabricating a trench capacitor, the method which comprises:
- forming a trench in a substrate;
- providing a sacrificial filling material in a lower region of the trench;
- forming a non-conformal layer in the trench having the sacrificial filling material in the lower region;
- removing at least a part of the non-conformal layer for uncovering the sacrificial filling material;
- removing the sacrificial filling material from the lower region of the trench;
- forming a buried plate in the substrate adjacent to the lower region of the trench as a first capacitor plate;
- forming a dielectric layer lining the lower region of the trench and lining an inner side of an insulation collar as a capacitor dielectric;
- and
- filling the trench with a conductive filling material as a second capacitor plate.
A method for fabricating a trench capacitor, the method which comprises:
- forming a trench in a substrate;
- forming a non-conformal layer in the trench;
- removing at least a part of the non-conformal layer in a lower region of the trench;
- forming a buried plate in the substrate adjacent to the lower region of the trench as a first capacitor plate;
- forming a dielectric layer lining the lower region of the trench and lining an inner side of an insulation collar as a capacitor dielectric;
- and
- filling the trench with a conductive filling material as a second capacitor plate.
A method for fabricating a trench capacitor, the method which comprises:
- forming a trench in a substrate;
- forming a conformal insulation collar layer in the trench;
- forming a sacrificial filling material in a lower region of the trench;
- forming a non-conformal sacrificial protective layer in an upper region of the trench;
- removing at least a part of the non-conformal sacrificial protective layer for uncovering the sacrificial filling material;
- removing the sacrificial filling material from the lower region of the trench;
- removing the insulation collar layer in the lower region of the trench for forming an insulation collar;
- forming a buried plate in the substrate adjacent to the lower region of the trench as a first capacitor plate;
- forming a dielectric layer lining the lower region of the trench and lining an inner side of the insulation collar as a capacitor dielectric;
- and
- filling the trench with a conductive filling material as a second capacitor plate.
Dependencies are inferred from the claim text.