Granted Patent B2

US 7,741,188 · App. 12/053,846 · Granted Jun 22, 2010

Abstract

Claims (39)

1. Method of forming a deep trench metal-insulator-metal (MIM) capacitor in an SOI-type substrate having a layer of silicon (SOI) atop a buried oxide (BOX) layer which is atop an underlying substrate, comprising:

forming a deep trench (DT) extending through the SOI layer and the BOX layer, and into the underlying substrate;

depositing a thin, conformal layer of a first conductive material to serve as a first of two conductive electrodes for a capacitor being formed in the deep trench;

removing a portion of the first conductive material from a top portion of the deep trench, recessing it to below the SOI layer;

depositing a dielectric layer covering sidewalls and a bottom of the deep trench, and the first conductive material;

filling the deep trench with a second conductive material, to serve as a second of the two conductive electrodes for a capacitor being formed in the deep trench; and

recessing the second conductive material so that its top surface is recessed below the SOI layer.

2. The method of claim 1 , wherein:

the underlying substrate is a silicon substrate;

the BOX layer has a thickness of 500-2500 Å; and

the SOI layer has a thickness of 50-200 Å.

3. The method of claim 1 , wherein:

the deep trench (DT) has a depth of 2000-5000 nm and a width of 50-150 nm.

4. The method of claim 1 , wherein:

the first conductive material comprises titanium nitride (TiN).

5. The method of claim 1 , wherein:

the first conductive material has a thickness of 5-10 nm.

6. The method of claim 1 , further comprising:

forming a buried plate in the underlying substrate, surrounding the deep trench.

7. The method of claim 1 , wherein:

the first conductive material is recessed to be above a top surface of the underlying substrate.

8. The method of claim 1 , wherein:

the first conductive material is recessed to be within the underlying substrate.

9. The method of claim 1 , wherein:

the dielectric layer comprises hafnium oxide.

10. The method of claim 1 , wherein:

the dielectric layer has a thickness of 2-6 nm.

11. The method of claim 1 , wherein:

the second conductive material comprises titanium nitride (TiN).

12. The method of claim 1 , wherein:

the second conductive material comprises a thin liner of titanium nitride (TiN) followed by a thick deposition of polysilicon.

13. The method of claim 1 , wherein:

the second conductive material is recessed to that its top surface is between bottom and top surfaces of the BOX layer.

14. The method of claim 1 , further comprising:

etching to expose an underside of the SOI layer.

15. The method of claim 1 , further comprising:

depositing polysilicon and etching it back to form a strap on top of the second conductive material.

16. The method of claim 15 , wherein:

the polysilicon is etched back to below a top surface of the SOI layer and above a bottom surface of the SOI layer.

Assignments (8)