Non-volatile memory cell with metal capacitor

• US 8,243,510 B2
• Filed: 08/30/2006
• Issued: 08/14/2012
• Est. Priority Date: 08/30/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chen, Andrew, Sahoo, Bibhudatta, Anvar, Ali
• Primary Examiner(s): NGUYEN, DANG T
• Application Number:
  US11/514,029
• Publication Number:
  US 20080054331A1
• Time in Patent Office: 2,176 Days
• Field of Search: 365/185.01, 365/185.14, 365/185.26, 365/104, 365/149, 365/212, 257/315, 257/314, 257/316
• US Class Current: 365/185.01
• CPC Class Codes: G11C 16/0416 comprising cells containing a single floating gate transistor and no select transistor, e.g. UV EPROM
• CPC Class Codes: G11C 16/0441 comprising cells containing multiple floating gate devices, e.g. separate read-and-write FAMOS transistors with connected floating gates
• CPC Class Codes: G11C 2216/10 Floating gate memory cells with a single polysilicon layer
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/42324 Gate electrodes for transistors with a floating gate
• CPC Class Codes: H01L 29/66825 with a floating gate H01L29/6684 takes precedence
• CPC Class Codes: H01L 29/7881 Programmable transistors with only two possible levels of programmation H01L29/7888 takes precedence
• CPC Class Codes: H10B 69/00 Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices

Abstract

According to one exemplary embodiment, a memory cell in a semiconductor chip includes a non-volatile memory transistor, a control gate, and a floating gate. The control gate is capacitively coupled to the floating gate of the non-volatile memory transistor by a metal capacitor. The metal capacitor can be formed in one or more metal levels and in one embodiment is in a shape of a comb with multiple fingers. In one embodiment, the non-volatile memory transistor is an NMOS non-volatile memory transistor.

Claims

1. A memory cell residing in a semiconductor chip, said memory cell comprising:

a non-volatile memory transistor comprising a floating gate;

a control gate being capacitively coupled to said floating gate by a metal capacitor comprising interconnect metal formed in one metal level of said semiconductor chip over an interlayer dielectric;

a metal interconnect coupling said metal capacitor and said floating gate, said metal interconnect formed in said one metal level;

wherein a state of said non-volatile memory transistor is read through a readout transistor coupled to said floating gate of said non-volatile memory transistor and a select transistor in series with said readout transistor.

2. The memory cell of claim 1 wherein said metal capacitor is shaped as a comb with a plurality of fingers.

3. The memory cell of claim 1 wherein said metal capacitor is formed in at least two metal levels of said semiconductor chip.

4. The memory cell of claim 1 wherein said metal capacitor comprises a plurality of metal plates, one of said plurality of metal plates having a control gate extension formed in said one metal.

5. A memory cell residing in a semiconductor chip, said memory cell comprising:

a non-volatile memory transistor comprising a floating gate;

a control gate being capacitively coupled to said floating gate by a metal capacitor comprising interconnect metal formed in one metal level of said semiconductor chip over an interlayer dielectric;

a metal interconnect coupling said metal capacitor and said floating gate, said metal interconnect formed in said one metal level;

wherein said metal capacitor is situated to one side of said floating gate such that no portion of said metal capacitor is situated directly above said floating gate.

6. The memory cell of claim 5 wherein said metal capacitor is shaped as a comb with a plurality of fingers.

7. The memory cell of claim 6 wherein said metal capacitor is formed in at least two metal levels of said semiconductor chip.

8. The memory cell of claim 5 wherein said metal capacitor comprises a plurality of metal plates, one of said plurality of metal plates having a control gate extension formed in said one metal level.

9. The memory cell of claim 5 wherein a state of said non-volatile memory transistor is read through a readout transistor and a select transistor coupled to said non-volatile memory transistor.

10. An electronic system comprising:

a semiconductor chip comprising at least one memory cell, said at least one memory cell comprising;

a non-volatile memory transistor comprising a floating gate;

a control gate being capacitively coupled to said floating gate by a metal capacitor comprising interconnect metal formed in one metal level of said semiconductor chip over an interlayer dielectric;

a metal interconnect coupling said metal capacitor and said floating gate, said metal interconnect formed in said one metal level;

wherein a state of said non-volatile memory transistor is read through a readout transistor coupled to said floating gate of said non-volatile memory transistor and a select transistor in series with said readout transistor.

11. The electronic system of claim 10 wherein said metal capacitor is shaped as a comb with a plurality of fingers.

12. The electronic system of claim 10 wherein said metal capacitor is formed in at least two metal levels of said semiconductor chip.

13. The memory cell of claim 10 wherein said metal capacitor comprises a plurality of metal plates, one of said plurality of metal plates having a control gate extension formed in said one metal level.

14. The electronic system of claim 10 wherein said electronic system is selected from the group consisting of a wired communications device, a wireless communications device, a cell phone, a switching device, a router, a repeater, a codec, a LAN, a WLAN, a Bluetooth enabled device, a digital camera, a digital audio player and/or recorder, a digital video player and/or recorder, a computer, a monitor, a television set, a satellite set top box, a cable modem, a digital automotive control system, a digitally-controlled home appliance, a printer, a copier, a digital audio or video receiver, an RF transceiver, a personal digital assistant (PDA), digital game playing device, a digital testing and/or measuring device, a digital avionics device, a medical device, and a digitally-controlled medical equipment.