Integrated circuit with floating-gate electrodes including a transition metal and corresponding manufacturing method

1. An integrated circuit comprising:

a semiconductor substrate;

an insulation layer on the semiconductor substrate;

a multitude of trenches formed through the insulation layer and into the semiconductor substrate

a multitude of floating-gate electrodes formed on portions of the insulation layer interposed between adjacent ones of the trenches, wherein at least one of the floating-gate electrodes has a lower width and an upper width, the lower width being larger than the upper width, and wherein the at least one of the floating-gate electrodes comprises a transition metal; and

a conductive layer on the insulation layer, wherein the trenches extend through the conductive layer so that portions of the conductive layer interposed between adjacent ones of the trenches form a lower part of the floating-gate electrodes disposed below an upper part of the floating-gate electrodes, the upper part formed by the transition metal and having a lower width and an upper width, the lower width being larger than the upper width.

2. The integrated circuit of claim 1 , wherein the at least one of the floating-gate electrodes comprises at least one of the materials: iridium or ruthenium.

3. The integrated circuit of claim 1 , wherein the at least one of the floating-gate electrodes comprises a transition metal oxide.

4. The integrated circuit of claim 3 , wherein the at least one of the floating-gate electrodes comprises at least one of the materials: iridium oxide or ruthenium oxide.

5. The integrated circuit of claim 1 , wherein the at least one of the floating-gate electrodes comprises at least one of the materials: a transition metal silicide, a transition metal nitride, a transition metal boride, a transition metal aluminide or a transition metal carbide.

6. The integrated circuit of claim 5 , wherein the transition metal is at least one of the elements: tungsten, molybdenum, tantalum, titanium, cobalt, zirconium, hafnium or niobium.

7. The integrated circuit of claim 6 , wherein the at least one of the floating-gate electrodes comprises at least one of the materials: tungsten silicide, molybdenum silicide, tantalum silicide, titanium silicide, cobalt silicide, zirconium silicide, hafnium silicide or niobium silicide.

8. The integrated circuit of claim 7 , wherein the at least one of the floating-gate electrodes comprises at least one of the materials: tungsten nitride, titanium nitride, tantalum nitride, hafnium nitride or zirconium nitride.

9. The integrated circuit of claim 1 , wherein the at least one of the floating-gate electrodes comprises a first subunit comprising the transition metal and a second subunit comprising a conductive material.

10. The integrated circuit of claim 1 , wherein the at least one of the floating-gate electrodes has an inverse-T shape.

11. The integrated circuit of claim 1 , wherein the integrated circuit is a semiconductor memory circuit.

12. The integrated circuit of claim 1 , further comprising an interface between the lower part and the upper part of the floating-gate electrodes with the lower part and the upper part being made of different materials.

13. The integrated circuit of claim 12 , wherein the lower part of the floating-gate electrodes comprises polysilicon.

14. The integrated circuit of claim 12 , wherein the material of the lower part of the floating-gate electrodes has a different etch rate than the material of the upper part of the floating-gate electrodes.

15. The integrated circuit of claim 1 , wherein the lower part of the floating-gate electrodes has a column-like shape and the upper part of the floating-gate electrodes has an inverse-T shape.