WO2006106571A1 - 半導体装置及び基準電圧生成方法 - Google Patents
半導体装置及び基準電圧生成方法 Download PDFInfo
- Publication number
- WO2006106571A1 WO2006106571A1 PCT/JP2005/006266 JP2005006266W WO2006106571A1 WO 2006106571 A1 WO2006106571 A1 WO 2006106571A1 JP 2005006266 W JP2005006266 W JP 2005006266W WO 2006106571 A1 WO2006106571 A1 WO 2006106571A1
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- Prior art keywords
- voltage
- reference cell
- cell
- output
- semiconductor device
- Prior art date
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Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C16/00—Erasable programmable read-only memories
- G11C16/02—Erasable programmable read-only memories electrically programmable
- G11C16/06—Auxiliary circuits, e.g. for writing into memory
- G11C16/26—Sensing or reading circuits; Data output circuits
- G11C16/28—Sensing or reading circuits; Data output circuits using differential sensing or reference cells, e.g. dummy cells
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/14—Dummy cell management; Sense reference voltage generators
Definitions
- the present invention relates to a semiconductor device, and in particular, a semiconductor device that generates a reference level at the time of reading or writing by using a reference cell provided separately from a memory cell, and performs writing of data to the memory cell and determination of read data. About.
- reading is performed separately from the memory cell, and a memory cell for reference at the time of reading the memory cell is provided.
- a core cell, a first internal reference cell, and a second internal reference cell are provided in the core cell region for storing data, and the reference voltage is output from the outputs of the first internal reference cell and the second internal reference cell.
- the core cell force is read and the reference data is compared with the read data to determine whether the data is 0 or 1.
- the core cell is deteriorated by rewriting or erasing data.
- a flash memory since information is stored according to the amount of charge stored in the charge storage layer, there is a deterioration phenomenon that the charge is lost over time. Therefore, by providing a reference cell in the core cell region, the data deterioration characteristics of the core cell data and the reference cell data can be made the same.
- the reference cell erased together with the core cell is reset after erasure.
- FIG. 1 shows threshold voltage distributions of the first internal reference cell and the second internal reference cell. Since there are multiple first and second reference cells, the threshold value has a certain width. Therefore, the reference voltage Vr ef generated from the average current when these are read out also has a certain width. Therefore, the reference voltage Vref can be made the same as the amount of change in the threshold voltage due to the deterioration of the core cell, but the read margin (A MGO, A MGl) is reduced.
- an external reference cell 104 is further provided as shown in FIG. 2, so that the first and second internal reference cells 102 and 103 and the external reference cell 104 are connected.
- the force also generates the reference voltage Vref. Since the external reference cell 104 does not rewrite data, it does not change with time. Moreover, since this is composed of one memory cell, the threshold does not have a distribution width. Therefore, by setting the average of the outputs of these three internal reference cells to the reference voltage Vref, it is possible to narrow the distribution of threshold voltages of virtual reference cells and to read data correctly.
- the virtual reference cell threshold voltage distribution is the sum of the voltage distributions of all reference cells used to generate the reference voltage, and is considered to be the threshold voltage distribution of one virtual reference cell. is there.
- Patent Document 1 Japanese Patent Publication No. 2004-110881
- the reference voltage Vref also generates the output of the external reference cell that does not change with time, and the output and force of the first reference cell and the second reference cell that change with time. Due to the change over time due to rewriting of the first reference cell and the second reference cell, the reference cell of '0' data approaches the voltage output by the external reference cell by AV2, and the reference cell of '1' data When the power is moved away from the voltage output by the external reference cell by ⁇ VI, the virtual reference cell distribution is
- the present invention has been made in view of the above circumstances, and a semiconductor device and a reference voltage that can set an optimum reference voltage in accordance with the amount of change with time of an internal reference cell.
- An object is to provide a pressure generation method.
- the semiconductor device of the present invention includes at least one reference cell and at least two current mirror circuits, and at least a voltage depending on a current flowing through the at least one reference cell is reduced.
- the cascode circuit that outputs to one output path, and a switch that selectively connects the at least two output paths to a predetermined output end.
- a semiconductor device includes at least one internal reference cell provided in a core cell region, at least one external reference cell provided outside the core cell region, and at least two current mirror circuits.
- a first cascode circuit that outputs a first voltage dependent on a current flowing through the at least one internal reference cell to at least two first output paths, and the selected first voltage is defined.
- a first switch that selectively connects the at least two first output paths to the predetermined output terminal, and a current flowing through the at least one external reference cell.
- a second cascode circuit for converting to the second voltage.
- the second cascode circuit includes at least two power lent mirror circuits, generates the second voltage from a current flowing through the at least one external reference cell, and Output second voltage to at least two second output paths
- the semiconductor device may include a second switch that selectively connects the at least two second output paths and the predetermined output end. Therefore, it is possible to increase or decrease the number of voltage outputs without increasing the number of external reference cells.
- the at least two first output paths and the at least two second output paths are short-circuited! Since these output paths are short-circuited, the output force of these paths can also generate a reference voltage.
- the at least one internal reference cell includes a first internal reference cell having a data 0 state and a second internal reference cell having a data 1 state,
- One external reference cell may have an intermediate state between data 0 and data 1. Therefore, the data written in the core cell can be read with high accuracy.
- the semiconductor device having the above configuration includes a sense amplifier that compares an output from the core cell with a reference voltage that is an average of outputs from the predetermined output terminals, and reads data stored in the core cell. It is good to have. Therefore, it is possible to accurately determine the data read from the core cell force.
- the semiconductor device having the above configuration may include a control circuit that controls the first switch and the second switch and changes the reference voltage to compensate for secular change. Therefore, it is possible to generate a reference voltage corresponding to the change characteristics of the reference cell over time.
- the reference voltage generation method of the present invention includes a step of generating a voltage from a current flowing in the reference cell and outputting the voltage to at least two output paths, and at least two output paths for obtaining the reference voltage. Selectively connecting to a predetermined output. Therefore, the reference voltage obtained from these voltages can be easily adjusted, and reading can be performed without reducing the margin when reading data from the core cell. The invention's effect
- FIG. 1 is a diagram showing a change in threshold distribution of a virtual reference cell that generates a reference voltage in a conventional nonvolatile memory.
- FIG. 2 is a configuration diagram showing a configuration of a conventional nonvolatile memory device.
- FIG. 3 is a diagram showing a change in threshold distribution of a virtual reference cell that generates a reference voltage in a conventional nonvolatile memory.
- FIG. 4 is a diagram showing a configuration of a semiconductor device of the present invention.
- FIG. 5 is a diagram showing a configuration of a cascode circuit.
- FIG. 6 is a diagram showing another configuration of the cascode circuit.
- FIG. 7 is a diagram showing a change in threshold distribution of a virtual reference cell that generates a reference voltage in the semiconductor device of the present invention.
- FIG. 8 is a flowchart showing an operation procedure.
- the semiconductor device 1 of the present embodiment is a nonvolatile semiconductor device in which two reference cell regions are provided in the core cell region 2 and one reference cell is provided outside the core cell region as shown in FIG.
- the memory cell in the core cell region 2 is a virtual ground type memory array, and includes an array of memory cells, a lead line, a bit line, and the like, and each memory cell stores 2-bit data.
- a film in which an oxide film, nitride film, and oxide film are stacked in this order is formed between the control gate and the substrate, and the threshold value is changed by trapping charges in this nitride film to change the data "0" Distinguish from “1 '.”
- the trap layer such as nitride film is an insulating film, so the charge does not move.
- a method of recording 2 bits in a cell is sometimes called a mirror bit method, and the cell array 5 may be a memory cell using a floating gate having a polycrystalline silicon force as a charge storage layer.
- the structure of the memory cell described here is an example, and can be widely applied to semiconductor devices having a configuration in which data of a core cell is determined and read using a reference cell.
- the first internal reference cell 4 has a data 0 state, for example, and the second internal reference cell 5 has a data 1 state.
- the external reference cell has an intermediate state between data 0 and data 1! /.
- the semiconductor device 1 is provided with a reference voltage generation circuit 10, cascode circuits 7 and 8, and a sense amplifier 9.
- a reference voltage generation circuit 10 selection circuits 11 and 20, cascode circuits 15 and 16, and a control circuit 17 are provided.
- the cascode circuit 16 (First voltage) is generated. Similarly, the cascode circuit 16 generates a voltage (first voltage) corresponding to the current flowing through the second internal reference cell 5. The cascode circuit 8 generates a voltage (second voltage) corresponding to the current flowing through the external reference cell 6.
- the output voltage of the cascode circuit 15 is output to the output paths 51 and 52 (first output path). These output paths 51 and 52 are provided with a switch SWAR1 (21) and a switch SWAR2 (22) (first switch), respectively.
- the switch SWAR1 (21) and the switch SWAR2 (22) are turned on / off by the control circuit 17 and output to the output voltage output terminal 27 of the cascode circuit 15.
- a switch is provided for each of the output paths 51 and 52.
- a switch may be provided for only one of the paths.
- the output voltage of the cascode circuit 16 is output to output paths 53 and 54 (first output path). These output paths 53 and 54 are provided with a switch SWBR1 (23) and a switch SWBR2 (24) (first switch), respectively.
- the switch SWBR1 (23) and the switch SWBR2 (24) are turned on / off by the control circuit 17 and output to the output voltage force output terminal 27 of the cascode circuit 16. It should be noted that a switch may be provided on only one of the paths in which the output paths 53 and 54 are each provided with a switch.
- the output voltage of the cascode circuit 8 is output to the output paths 55 and 56 (second output path).
- These output paths 55 and 56 are each provided with a switch SWXR1 (25) and a switch SWXR2 (26) (second switch).
- a switch may be provided for only one of the V and shift paths.
- Cascode circuits 15, 16, 8 by turning on switches SWAR1 (21), SWAR2 (22), SWBR1 (23), SW BR2 (24), SWXR1 (25), SWXR2 (26) in selection circuit 20 Is short-circuited, and a voltage is output to the specified output terminal 27.
- the reference voltage Vref is generated from the average value of the voltage output to the output terminal 27.
- the control circuit 17 includes, for example, a non-volatile trimming memory cell, and presets the information in the trimming memory cell in accordance with the deterioration characteristics of the memory cell obtained at the time of product evaluation.
- the switches SWAX12, SWAB13, SWBX14 in the selection circuit 11 and the switches SWAR1, SWAR2, SWAR1, SWAR2, SWXR1, SWXR2 in the selection circuit 20 are controlled to be turned on / off. Therefore, after the product is shipped, the on / off state of the predetermined switch is determined by the trimming memory cell.
- a part of the core cell may be used as the trimming memory cell.
- the sense amplifier 9 is a signal obtained by converting the reference voltage Vref from the reference voltage generation circuit 10 and the data output (current) from the core cell 3 into current-voltage converted by the cascode circuit 7 (any memory cell power in the core cell 3). Compared with the read data voltage (voltage determined by the threshold value of the memory cell from which data is read), it is determined whether the read data output from the core cell 3 is “0” or “1”. To do.
- FIG. 5 shows the configuration of the cascode circuit 15. Since the other cascode circuits 8 and 16 have the same configuration as the cascode circuit 15, their description is omitted.
- the cascode circuit 15 includes a p-channel MOS transistor 30 and an n-channel MOS transistor 31 connected in series, and a first internal reference cell 4 connected to the source side of the nMOS transistor! / RU Further, the gate electrode of the p-channel MOS transistor 33 and the gate electrode of the pMOS transistor 34 are connected to the gate electrode of the p-channel MOS transistor 30 to constitute a current mirror circuit.
- the voltage of the node 35 which is the connection point between the p-channel MOS transistor 30 and the n-channel MOS transistor 31, varies depending on the current I flowing through the internal reference cell. That is, When the current I flowing through the internal reference cell increases, the voltage at the node 35 decreases, and when the current amount I flowing through the internal reference cell decreases, the voltage at the node 35 increases.
- This voltage change at node 35 is transmitted to SA1 and SA2 on the drain side of ⁇ -channel MOS transistors 33 and 34 by a current mirror circuit.
- a constant current source of IL is connected to SA1 and SA2 as a load.
- the constant current source is a resistor having a polysilicon force, for example.
- a switch SWAR1 controlled by the control circuit 17 is placed between the SA1 and the output terminal, and a switch SWAR2 controlled by the control circuit 17 is placed between the SA2 and the output terminal.
- a switch SWAR1 and SWAR2 By closing switches SWAR1 and SWAR2, the output of other cascode circuits 16 and 8 and the averaged reference voltage Vref are output to sense amplifier 9. Note that only one of the switches SWAR1 and SWA R2 may be formed.
- the reference voltage Vref corresponding to the characteristics of the internal reference cell can be created by switching on / off the switches SWAR1, SWAR2, SWBR1, SWBR2, SWXRl, and SWXR2. For example, by turning on the switches SWAR1, SWAR2, SWBR1, and SWBR2 and the switch SWXR1 of the external reference cell, twice the current that flows in the first reference cell 4 and twice that that flows in the second reference cell 5 A reference voltage Vref is generated, which is the current and a current that is 1x the current that flows to the external reference cell.
- FIG. 6 shows a modification of the cascode circuit 15.
- MOS transistors 36, 37, 38, and 39 are provided on the Vcc power supply side of the p-channel MOS transistors 33 and 34 and the Vss power supply side of the constant current source IL. These MOS transistors have the same function as switches SWAR1 and SWAR2. In this configuration, since the parasitic capacitance caused by the switch is not attached to the node of the reference voltage Vref, a highly accurate Vref can be generated.
- the MOS transistor may be formed only on either the SA1 side or the SA2 side.
- the reference voltage Vref can be easily adjusted according to the degree of deterioration of the first internal reference cell 4 and the second internal reference cell 5 due to changes over time. Therefore, the reference voltage Vref without increasing the number of reference cells can be changed with time, and reading can be performed without reducing the margin.
- the control circuit 17 selects and turns on the switch to be turned on among the switches of the selection circuit 20 according to the deterioration characteristics of the memory cell obtained at the time of product evaluation.
- the first and second internal reference cells 4 and 5 and the external reference cell 6 are selected to pass a cell current (step S2), and this current is passed through the cascode circuits 15, 16, and 8, respectively. Convert to voltage (step S3).
- the switch-on path is connected to the output terminal 27 shown in FIG. 4, and the reference voltage Vref is generated from the outputs of the first and second internal reference cells 4 and 5 and the external reference cell 6 (step S4). .
- the reference voltage Vref is compared with the voltage converted value of the current flowing through the core cell 3, and the data written in the core cell 3 is determined (step S5).
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007512375A JP4763689B2 (ja) | 2005-03-31 | 2005-03-31 | 半導体装置及び基準電圧生成方法 |
PCT/JP2005/006266 WO2006106571A1 (ja) | 2005-03-31 | 2005-03-31 | 半導体装置及び基準電圧生成方法 |
US11/392,398 US7321513B2 (en) | 2005-03-31 | 2006-03-28 | Semiconductor device and method of generating a reference voltage therefor |
TW095111153A TW200705151A (en) | 2005-03-31 | 2006-03-30 | Semiconductor device and method of generating a reference voltage therefor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/JP2005/006266 WO2006106571A1 (ja) | 2005-03-31 | 2005-03-31 | 半導体装置及び基準電圧生成方法 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/392,398 Continuation US7321513B2 (en) | 2005-03-31 | 2006-03-28 | Semiconductor device and method of generating a reference voltage therefor |
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WO2006106571A1 true WO2006106571A1 (ja) | 2006-10-12 |
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PCT/JP2005/006266 WO2006106571A1 (ja) | 2005-03-31 | 2005-03-31 | 半導体装置及び基準電圧生成方法 |
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US (1) | US7321513B2 (ja) |
JP (1) | JP4763689B2 (ja) |
TW (1) | TW200705151A (ja) |
WO (1) | WO2006106571A1 (ja) |
Families Citing this family (5)
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WO2007000809A1 (ja) * | 2005-06-28 | 2007-01-04 | Spansion Llc | 半導体装置およびその制御方法 |
US7961519B2 (en) * | 2009-06-29 | 2011-06-14 | Spansion Llc | Memory employing independent dynamic reference areas |
US7940570B2 (en) | 2009-06-29 | 2011-05-10 | Spansion Llc | Memory employing separate dynamic reference areas |
TWI766462B (zh) * | 2019-12-23 | 2022-06-01 | 美商美光科技公司 | 在記憶體裝置中基於計數器之讀取 |
WO2021130510A1 (en) * | 2019-12-23 | 2021-07-01 | Micron Technology, Inc. | Counter-based read in memory device |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS625422A (ja) * | 1985-06-29 | 1987-01-12 | Toshiba Corp | 半導体集積回路装置 |
JP2001094055A (ja) * | 1999-09-24 | 2001-04-06 | Toshiba Corp | 半導体装置およびその基準電位調整方法 |
JP2004110881A (ja) * | 2002-09-13 | 2004-04-08 | Fujitsu Ltd | 半導体記憶装置 |
JP2004363887A (ja) * | 2003-06-04 | 2004-12-24 | Casio Comput Co Ltd | 電流生成供給回路 |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5608676A (en) * | 1993-08-31 | 1997-03-04 | Crystal Semiconductor Corporation | Current limited current reference for non-volatile memory sensing |
JP3999151B2 (ja) * | 2003-03-20 | 2007-10-31 | スパンション エルエルシー | 半導体記憶装置 |
-
2005
- 2005-03-31 JP JP2007512375A patent/JP4763689B2/ja not_active Expired - Fee Related
- 2005-03-31 WO PCT/JP2005/006266 patent/WO2006106571A1/ja not_active Application Discontinuation
-
2006
- 2006-03-28 US US11/392,398 patent/US7321513B2/en not_active Expired - Fee Related
- 2006-03-30 TW TW095111153A patent/TW200705151A/zh unknown
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS625422A (ja) * | 1985-06-29 | 1987-01-12 | Toshiba Corp | 半導体集積回路装置 |
JP2001094055A (ja) * | 1999-09-24 | 2001-04-06 | Toshiba Corp | 半導体装置およびその基準電位調整方法 |
JP2004110881A (ja) * | 2002-09-13 | 2004-04-08 | Fujitsu Ltd | 半導体記憶装置 |
JP2004363887A (ja) * | 2003-06-04 | 2004-12-24 | Casio Comput Co Ltd | 電流生成供給回路 |
Also Published As
Publication number | Publication date |
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US7321513B2 (en) | 2008-01-22 |
JP4763689B2 (ja) | 2011-08-31 |
TW200705151A (en) | 2007-02-01 |
US20070035993A1 (en) | 2007-02-15 |
JPWO2006106571A1 (ja) | 2008-09-11 |
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