Nano-sense amplifier

• US 8,625,374 B2
• Filed: 12/18/2012
• Issued: 01/07/2014
• Est. Priority Date: 03/11/2010
• Status: Active Grant

• Current Assignee: Soitec S.A.
• Original Assignee: Soitec S.A.
• Inventors: Mazure, Carlos, Ferrant, Richard, Nguyen, Bich-Yen
• Primary Examiner(s): Le, Thong Q
• Application Number:
  US13/718,571
• Publication Number:
  US 20130100749A1
• Time in Patent Office: 385 Days
• Field of Search: 365/148, 365/177, 365/185.17, 365/203, 365/205, 365/230.03, 365/230.06, 365/63
• US Class Current: 365/205
• CPC Class Codes: G11C 11/4091 Sense or sense/refresh amplifiers, or associated sense circuitry, e.g. for coupled bit-line precharging, equalising or isolating
• CPC Class Codes: G11C 11/4097 Bit-line organisation, e.g. bit-line layout, folded bit lines
• CPC Class Codes: G11C 2211/4016 Memory devices with silicon-on-insulator cells
• CPC Class Codes: G11C 7/06 Sense amplifiers; Associated circuits , e.g. timing or triggering circuits
• CPC Class Codes: G11C 7/067 Single-ended amplifiers
• CPC Class Codes: G11C 7/08 Control thereof
• CPC Class Codes: G11C 7/18 Bit line organisation; Bit line lay-out

Abstract

A sense amplifier for a series of cells of a memory, including a writing stage comprising a CMOS inverter, the input of which is directly or indirectly connected to an input terminal of the sense amplifier, and the output of which is connected to an output terminal of the sense amplifier intended to be connected to a local bitline addressing the cells of the series, and a reading stage that includes a sense transistor, the gate of which is connected to the output of the inverter and the drain of which is connected to the input of the inverter.

Claims

1. A sense amplifier (nSA) of a series of cells (Ci, Cj) of a memory, including:

a writing stage comprising a CMOS inverter (T1-T2), the input of which is directly or indirectly connected to an input terminal of the sense amplifier, and the output of which is connected to an output terminal of the sense amplifier intended to be connected to a local bitline (LBL) addressing the cells of said series, and

a reading stage comprising a sense transistor (T3), the gate of which is connected to the output of the inverter and the drain of which is connected to the input of the inverter,

wherein one or more of the transistors are multigate transistors.

2. The sense amplifier according to claim 1, wherein at least one multigate transistor is a FinFET.

3. The sense amplifier according to claim 1, wherein the input of the writing stage is directly connected to the input terminal of the inverter, said input terminal being intended to be connected to a main bitline (MBL) which will address a plurality of sense amplifiers in parallel.

4. The sense amplifier according to claim 1, wherein the reading stage comprises an additional transistor (T4) complementary to the sense transistor, the additional transistor and the sense transistor forming a CMOS inverter, the input of which is connected to the output of the reading stage and the output of which is connected to the input of the inverter of the writing stage.

5. The sense amplifier according to claim 4, wherein the input of the writing stage is indirectly connected to the input terminal of the inverter via a decoding stage comprising a transistor (T5), the drain of which is connected to the input terminal of the sense amplifier and the source of which is connected to the input of the writing stage.

6. The sense amplifier according to claim 1, which is made on a semiconductor-on-insulator substrate comprising a thin layer of semiconducting material separated from a base substrate by an insulating layer, and wherein each of the transistors has a back control gate formed in the base substrate below the channel and capable of being biased in order to modulate the threshold voltage of the transistor.

7. A method for controlling a sense amplifier according to claim 1, which comprises modifying the biasing of one of the gates of the transistors during operations for writing, reading or retaining of data in the cells of the series.

8. A method for controlling a sense amplifier according to claim 7, which comprises modifying the biasing of the back control gates during operations for writing, reading and retaining data in the cells of the series.

9. The method according to claim 8, wherein the biasing of the back control gates is controlled during a reading operation to increase the threshold voltage of the transistors of the writing stage and to reduce the threshold voltage of the transistor(s) of the reading stage.

10. The method according to claim 8, wherein the biasing of the back control gates is controlled during a writing operation to reduce the threshold voltage of the transistors of the writing stage and to increase the threshold voltage of the transistor(s) of the reading stage.

11. The method according to claim 8, wherein during a retention operation, the local bitline is discharged via one of the transistors of the writing stage, for which the biasing of the back control gate is controlled so as to lower its threshold voltage.

12. A main sense amplifier (MSA) intended to be connected via a main bitline (MBL) to a plurality of sense amplifiers according to claim 1, comprising a step for amplifying the signal (T6-T10) delivered by a cell during a reading operation, and a switchable high impedance inverter stage (HZ1) for sending back the amplified signal onto the main bitline following the reading operation.

14. A matrix array of cells connected to local bitlines and to wordlines, comprising a sense amplifier according to claim 1.

15. A matrix array of cells according to claim 14, wherein the sense amplifiers are made on a semiconductor-on-insulator substrate.

16. A matrix array of cells according to claim 15, wherein the sense amplifiers are arranged in one or more sense amplifier banks and further comprising a column decoder placed next to each bank and configured to drive said bank directly.

17. A matrix array of cells according to claim 16, further comprising logic circuits placed next to the sense amplifier banks or the column decoder.

18. A memory including a matrix array of cells according to claim 14.

20. A method for controlling a sense amplifier according to claim 1, which comprises modifying the biasing of one of the gates of the transistors during operations for writing, reading or retaining of data in the cells of the series.

13. A sense amplifier (nSA) including:

a writing stage comprising a CMOS inverter (T1-T2), the input of which is directly or indirectly connected to an input terminal of the sense amplifier, and the output of which is connected to an output terminal of the sense amplifier intended to be connected to a local line, and

a reading stage comprising a sense transistor (T3), the gate of which is connected to the output of the inverter and the drain of which is connected to the input of the inverter;

wherein one or more transistors of the writing stage and of the reading stage are independent double gate transistors.

19. A matrix array of cells comprising sense amplifiers and column decoders, wherein the sense amplifiers are arranged in a non-staggered fashion in one or more sense amplifier banks and wherein a column decoder is placed next to each bank and configured to drive said bank directly.