Integrated circuit including a voltage divider and methods of operating the same

• US 8,780,628 B2
• Filed: 09/23/2011
• Issued: 07/15/2014
• Est. Priority Date: 09/23/2011
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lin, Yvonne, Chu, Wen-Ting
• Primary Examiner(s): Ho, Hoai V
• Assistant Examiner(s): HUERTA, PABLO S
• Application Number:
  US13/241,932
• Publication Number:
  US 20130076335A1
• Time in Patent Office: 1,026 Days
• Field of Search: 365/185.05
• US Class Current: 365/185.05
• CPC Class Codes: G11C 16/0408 comprising cells containing floating gate transistors G11C16/0483, G11C16/0491 take precedence
• CPC Class Codes: G11C 16/08 Address circuits; Decoders; Word-line control circuits
• CPC Class Codes: G11C 29/82 for EEPROMs
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 27/0802 Resistors only
• CPC Class Codes: H01L 27/0805 Capacitors only
• CPC Class Codes: H01L 28/60 Electrodes
• CPC Class Codes: H01L 29/94 Metal-insulator-semiconductors, e.g. MOS
• CPC Class Codes: H10B 41/40 characterised by the peripheral circuit region

Abstract

An integrated circuit includes at least one FLASH memory array and at least one capacitor array disposed over a substrate. The at least one capacitor array includes a plurality of capacitor cell structures. The capacitor cell structures each includes a first capacitor electrode disposed over the substrate. A second capacitor electrode is disposed over the first capacitor electrode. A third capacitor electrode is disposed adjacent to first sidewalls of the first and second capacitor electrodes. A fourth capacitor electrode is disposed adjacent to second sidewalls of the first and second capacitor electrodes.

Claims

1. An integrated circuit comprising:

at least one FLASH memory array disposed over a substrate; and

at least one capacitor array including a plurality of capacitor cell structures disposed over the substrate, the capacitor cell structures each comprising;

a first capacitor electrode disposed over the substrate;

a second capacitor electrode disposed over the first capacitor electrode;

a third capacitor electrode disposed adjacent to first sidewalls of the first and second capacitor electrodes, the first sidewalls on a same side of the first and second electrodes being entirely vertically displaced from one another with respect to a surface of the substrate, and the first sidewalls on a same side of the first and second electrodes being substantially aligned; and

a fourth capacitor electrode disposed adjacent to second sidewalls of the first and second capacitor electrodes.

2. The integrated circuit of claim 1, wherein the capacitor cell structures each further comprise:

a fifth capacitor electrode disposed over the substrate and adjacent to the fourth capacitor electrode;

a sixth capacitor electrode disposed over the fifth capacitor electrode and adjacent to the fourth capacitor electrode; and

a seventh capacitor electrode disposed over the substrate and adjacent to sidewalls of the fifth and sixth capacitor electrodes.

3. The integrated circuit of claim 2, wherein

the second capacitor electrode is configured to receive a first voltage level;

the sixth capacitor electrode is electrically grounded; and

the first, fourth and fifth capacitor electrodes are electrically coupled to each other and are configured to provide a second voltage level that is smaller than the first voltage level.

4. The integrated circuit of claim 2, wherein

the first and second capacitor electrodes are configured to receive a third voltage level;

the fifth and sixth capacitor electrodes are electrically grounded; and

the fourth capacitor electrode is configured to provide a fourth voltage level that is smaller than the third voltage level.

5. The integrated circuit of claim 2, wherein

the first capacitor electrode is configured to receive a fifth voltage level;

the fifth capacitor electrode is electrically grounded; and

the second, fourth and sixth capacitor electrodes are electrically coupled to each other and are configured to provide a sixth voltage level that is smaller than the fifth voltage level.

6. The integrated circuit of claim 1, wherein the capacitor cell structures each further comprises:

a fifth capacitor electrode disposed in the substrate and adjacent to a sidewall of the third capacitor electrode; and

a sixth capacitor electrode disposed in the substrate and below the fourth capacitor electrode.

7. The integrated circuit of claim 6, wherein the fifth and sixth capacitor electrodes each comprise a doped region in the substrate.

8. The integrated circuit of claim 1, wherein the capacitor cell structures each further comprises:

a first capacitor dielectric structure disposed between the substrate and the first capacitor electrode;

a second capacitor dielectric structure disposed between the first and second capacitor electrodes, wherein the first capacitor dielectric structure is different from the second capacitor dielectric structure;

a third capacitor dielectric structure disposed between the third capacitor electrode and the first sidewalls of the first and second capacitor electrodes; and

a fourth capacitor dielectric structure disposed between the fourth capacitor electrode and the second sidewalls of the first and second capacitor electrodes.

9. The integrated circuit of claim 8, wherein the first capacitor dielectric structure comprises a silicon oxide layer and the second capacitor dielectric structure comprises a silicon oxide/silicon nitride (ON) structure.

10. The integrated circuit of claim 1, wherein at least one FLASH memory array comprises a plurality of FLASH memory cells and each of the plurality of FLASH memory cells comprises:

a floating gate disposed over the substrate;

a control gate disposed over the floating gate;

a word line disposed adjacent to first sidewalls of the floating gate and the control gate;

an erase gate disposed adjacent to second sidewalls of the floating gate and the control gate;

a first source/drain (S/D) region disposed in the substrate and adjacent to a sidewall of the word line; and

a second S/D region disposed in the substrate and below the erase gate.

11. An integrated circuit comprising:

at least one FLASH memory array disposed over a substrate, wherein the at least one FLASH memory array comprises a plurality of FLASH memory cells and each of the plurality of FLASH memory cells comprises;

a floating gate disposed over the substrate;

a control gate disposed over the floating gate;

a word line disposed adjacent to first sidewalls of the floating gate and the control gate;

an erase gate disposed adjacent to second sidewalls of the floating gate and the control gate;

a first source/drain (S/D) region disposed in the substrate and adjacent to a sidewall of the word line; and

a second S/D region disposed in the substrate and below the erase gate; and

at least one capacitor array including a plurality of capacitor cell structures disposed over the substrate, the capacitor cell structures each comprising;

a first capacitor electrode disposed over the substrate;

a second capacitor electrode disposed over the first capacitor electrode;

a third capacitor electrode disposed adjacent to first sidewalls of the first and second capacitor electrodes;

a fourth capacitor electrode disposed adjacent to second sidewalls of the first and second capacitor electrodes;

a fifth capacitor electrode disposed over the substrate and adjacent to the fourth capacitor electrode;

a sixth capacitor electrode disposed over the fifth capacitor electrode and adjacent to the fourth capacitor electrode; and

a seventh capacitor electrode disposed over the substrate and adjacent to sidewalls of the fifth and sixth capacitor electrodes.

12. The integrated circuit of claim 11, wherein

the second capacitor electrode is configured to receive a first voltage level;

the sixth capacitor electrode is electrically grounded; and

the first, fourth and fifth capacitor electrodes are electrically coupled to each other and are configured to provide a second voltage level that is smaller than the first voltage level.

13. The integrated circuit of claim 11, wherein

the first and second capacitor electrodes are configured to receive a third voltage level;

the fifth and sixth capacitor electrodes are electrically grounded; and

the fourth capacitor electrode is configured to provide a fourth voltage level that is smaller than the third voltage level.

14. The integrated circuit of claim 11, wherein

the first capacitor electrode is configured to receive a fifth voltage level;

the fifth capacitor electrode is electrically grounded; and

the second, fourth and sixth capacitor electrodes are electrically coupled to each other and are configured to provide a sixth voltage level that is smaller than the fifth voltage level.

15. The integrated circuit of claim 11, wherein the capacitor cell structures each further comprises:

an eighth capacitor electrode disposed in the substrate and adjacent to a sidewall of the third capacitor electrode; and

a ninth capacitor electrode disposed in the substrate and below the fourth capacitor electrode, wherein the eighth and ninth capacitor electrodes each comprise a doped region in the substrate.

16. The integrated circuit of claim 11, wherein the capacitor cell structures each further comprises:

a first capacitor dielectric structure comprising a silicon oxide layer disposed between the substrate and the first capacitor electrode;

a second capacitor dielectric structure comprising a silicon oxide/silicon nitride (ON) structure disposed between the first and second capacitor electrodes;

a third capacitor dielectric structure disposed between the third capacitor electrode and the first sidewalls of the first and second capacitor electrodes; and

a fourth capacitor dielectric structure disposed between the fourth capacitor electrode and the second sidewalls of the first and second capacitor electrodes.

17. A method of operating a voltage divider, the voltage divider comprising a plurality of capacitor cell structures over a substrate, the capacitor cell structures each comprising a first capacitor electrode disposed over the substrate, a second capacitor electrode disposed over the first capacitor electrode, a third capacitor electrode disposed adjacent to first sidewalls of the first and second capacitor electrodes, a fourth capacitor electrode disposed adjacent to second sidewalls of the first and second capacitor electrodes, a fifth capacitor electrode disposed over the substrate and adjacent to the fourth capacitor electrode, a sixth capacitor electrode disposed over the fifth capacitor electrode and adjacent to the fourth capacitor electrode, and a seventh capacitor electrode disposed over the substrate and adjacent to sidewalls of the fifth and sixth capacitor electrodes, the method comprising:

applying a first voltage level to at least first one of the first to seventh capacitor electrodes;

electrically grounding at least second one of the first to seventh capacitor electrodes; and

electrically coupling at least third one of the first to seventh capacitor electrodes to provide a second voltage level on an output node of the voltage divider, wherein the second voltage level is smaller than the first voltage level.

18. The method of claim 17, wherein

the at least first one of the first to seventh capacitor electrodes comprises the second capacitor electrode;

the at least second one of the first to seventh capacitor electrodes comprises the sixth capacitor electrode; and

the at least third one of the first to seventh capacitor electrodes comprises the first, fourth and fifth capacitor electrodes.

19. The method of claim 17, wherein

the at least first one of the first to seventh capacitor electrodes comprises the first and second capacitor electrodes;

the at least second one of the first to seventh capacitor electrodes comprises the fifth and sixth capacitor electrodes; and

the at least third one of the first to seventh capacitor electrodes comprises the fourth capacitor electrode.

20. The method of claim 17, wherein

the at least first one of the first to seventh capacitor electrodes comprises the first capacitor electrode;

the at least second one of the first to seventh capacitor electrodes comprises the fifth capacitor electrode; and

the at least third one of the first to seventh capacitor electrodes comprises the second, fourth and sixth capacitor electrodes.