KR101128715B1 - A cell of nonvolatile memory device, operating method and manufacturing method thereof - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a nonvolatile memory cell, a method of operating data and a method of manufacturing the data of the nonvolatile memory cell, which can reduce the manufacturing cost by simplifying the manufacturing process in manufacturing the nonvolatile memory cell. Is connected to a word line, a bit line crossing the word line, a program line extending in parallel with the bit line to intersect the word line, and a point at which the word line and the bit line cross each other. A first select transistor selected by a line, a second select transistor selected by the word line at an intersection of the word line and the program line, and connected between the first select transistor and the select line, A first bias and the selection transmitted through the first selection transistor during a program operation Electrons are injected into the cell gate by a second bias applied through phosphorus, and are connected between the second selection transistor and the selection line to perform a program operation, and the second selection transistor during an erase operation. And a second cell transistor in which holes are injected into the cell gate by the first bias transferred through the second bias and the second bias transferred through the selection line, thereby performing an erase operation.

EEPROM cells, PMOS, NMOS, floating gates, electrons, holes.

Description

Non-volatile memory cell, operation method thereof and manufacturing method thereof {A CELL OF NONVOLATILE MEMORY DEVICE, OPERATING METHOD AND MANUFACTURING METHOD THEREOF}

1 is an equivalent circuit diagram of an EEPROM cell according to the prior art.

2 is a plan view of the EEPROM cell shown in FIG.

3A to 3C are cross-sectional views taken along the lines A-A ', B-B' and C-C ', respectively.

4 is an equivalent circuit diagram of an EEPROM cell in accordance with a preferred embodiment of the present invention.

5 is a plan view of the EEPROM cell shown in FIG.

6A to 6C are cross-sectional views taken along the lines A-A ', B-B' and C-C ', respectively.

7A to 7D are cross-sectional views illustrating a method of manufacturing the EEPROM cell shown in FIG. 5.

Description of the Related Art

BL: Bitline PL: Program Line

WL: Word line SL: Selection line

ST ₁ , ST ₂ : first select transistor, second select transistor

CT ₁ , CT ₂ : first cell transistor, second cell transistor

TR: tunneling region 11, 111: semiconductor substrate

12, 113: device isolation layer 13: N + buried layer

112: N well 114: First gate insulating film

115: second gate insulating film 14: control gate

17, 116a: floating gate 116b: first gate electrode

116c: second gate electrodes 117a and 118a: source region

117b and 118b: drain region 18 and 119: contact plug

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonvolatile memory cell, an operation method thereof, and a manufacturing method thereof, and more particularly, to an EEPROM (Electric Erasable Programmable Read Only Memory) cell, an operation method thereof, and a manufacturing method thereof.

Recently, the use of smart cards that can hold various functions in one card such as ID card, credit card and electronic money has been gradually expanded. A smart card stores user information and transaction information and has a built-in program for that purpose. Accordingly, a smart card usually includes nonvolatile memory cells for recording and storing user information and transaction information, and a mask ROM for coding a predetermined program in the form of a single chip.

As nonvolatile memory cells, flash cells, erasable programmable read only memory (EPROM) cells, and electrical EPROM (EEPROM) cells are widely used. Among them, an EEPROM cell includes a single poly (1-poly) structure EEPROM cell and an EEPROM cell having a stack structure.

Hereinafter, an EEPROM cell having a single poly structure according to the prior art will be described with reference to FIGS. 1, 2, and 3A to 3C. 1 is an equivalent circuit diagram of an EEPROM cell according to the prior art, and FIG. 2 is a plan view of the EERPOM cell shown in FIG. 3A is a cross-sectional view taken along line AA ′ of FIG. 2, FIG. 3B is a cross-sectional view taken along line BB ′ of FIG. 2, and FIG. 3C is a cross-sectional view taken along line CC ′ of FIG. 2. It is a cross-sectional view shown.

As shown in FIGS. 1, 2 and 3A to 3C, an EEPROM cell according to the prior art is connected between a cell transistor CT in which data is stored, and a cell transistor CT and a bit line BL. Is connected between the selection transistor ST ₁ (hereinafter referred to as a first selection transistor) selected by the word line WL, the cell transistor CT and the program line PL, and is connected to the word line WL. Select transistor ST ₂ (hereinafter referred to as a second select transistor).

As illustrated in FIG. 3A, an N + buried layer 13 is formed in a predetermined region inside the semiconductor substrate 11, and a control gate 14 is formed in the N + buried layer 13. The gate insulating film 15 and the tunnel oxide film 16 are formed in a predetermined region on the semiconductor substrate 11 on which the control gate 14 is formed. The floating gate 17 is formed on the gate insulating film 15 and the tunnel oxide film 16. At this time, the tunnel oxide film 16 is formed thinner than the gate insulating film 15. Although not shown, '12' is an isolation layer and '18' is a contact plug.

As shown in FIG. 3B, the first selection transistor ST ₁ includes a gate insulating film 15 formed on the semiconductor substrate 11, a first gate electrode 20a formed on the gate insulating film 15, and It consists of the source / drain regions 21 formed in the substrate 11 exposed on both sides of the one gate electrode 20a.

As shown in FIG. 3C, the second select transistor ST ₂ is disposed on both sides of the gate insulating film 15, the second gate electrode 20b formed on the gate insulating film 15, and the second gate electrode 20b. It consists of a source / drain region 21 formed in the exposed substrate 11.

Although not illustrated, 'C ₂ ' illustrated in FIG. 1 is a capacitance of the gate insulating layer 15 interposed between the control gate 14 and the floating gate 17, and 'C ₁ ' is a floating gate 17. ) And the tunnel oxide film 16 interposed between the semiconductor substrate 11 and the semiconductor substrate 11.

Hereinafter, a method of operating a read, erase and program of an EEPROM cell according to the related art having such a configuration will be described with reference to Table 1 below.

The conventional EEPROM cell performs erase and program operations using F-N tunneling (Fouler Nordheim Tunneling). FN tunneling refers to a high field applied to the tunnel oxide layer 16 to inject electrons from the semiconductor substrate 11 into the floating gate 17 so that an erase operation is performed and electrons injected through the erase operation. Is a mechanism for causing a program operation to be performed by releasing the to the semiconductor substrate 11. In this case, the semiconductor substrate 11 is connected to the program line PL. Meanwhile, the erase and program operations may be performed in a manner different from that described above, depending on the device.

Operation mode Mechanism WL Control gate PL SL BL elimination F-N Tunneling V _CC V _PP GND V _CC Floating program F-N Tunneling V _CC GND V _PP V _CC Floating Reading - V _CC GND GND GND Vread

Read action

As electrons are injected or emitted into the floating gate 17, the threshold voltage of the memory cell changes. At this time, the difference of the current according to the change of the threshold voltage is sensed to read the data of the EEPR0M cell.

For the read operation of the EEPROM cell, the select transistor ST ₁ is turned on, a read voltage Vread is applied to the bit line BL, for example, a read voltage of 1 to 2 V, and then the bit line Identify the current flowing in BL). At this time, when the threshold voltage of the floating gate 17 is 0V or less, current flows, and when it exceeds OV, current does not flow.

As a result, the program state is recognized as less than OV, and the erase state is exceeded when OV is exceeded.

Erase operation

For the erasing operation of the conventional EEPROM cell, that is, in order to allow the threshold voltage of the transistor to exceed OV, a high voltage Vpp of 15 V or less should be applied to the control gate 14.

That is, when a high voltage Vpp is applied to the control gate 14, F-N tunneling is performed in the terminating region TR, and electrons are injected from the program line PL to the floating gate 17. When electrons are injected into the floating gate 17, the floating gate 17 becomes (−) and the threshold voltage becomes 2V or more, so that the erase operation is performed.

At this time, since the capacitance by the gate insulating film 15 interposed between the control gate 14 and the floating gate 17 is larger than the capacitance by the tunnel oxide film 16 formed in the tunneling region TR, the tunnel oxide film ( FN tunneling is performed in the tunneling region TR in which 16 is formed.

Program behavior

For the program operation of the EEPROM cell according to the prior art, that is, in order to make the threshold voltage of the transistor to 0V or less, high voltage Vpp should be applied to the program line PL.

That is, when the high voltage Vpp is applied to the program line PL, F-N tunneling is performed in the tunneling region TR to emit electrons from the floating gate 17 to the program line PL. When electrons are emitted from the floating gate 17, the floating gate 17 becomes (+), and the threshold voltage becomes -2V or less.

However, the conventional EEPROM cell and its operation method have various problems as follows.

First, in order to fabricate an EEPROM cell as in the prior art, at least two or more mask processes are required to manufacture a standard logic device. For example, in order to form the cell transistor CT, an N + buried layer 13 needs to be formed, and therefore, a separate mask process and an impurity ion implantation process for forming the N + buried layer 13 need to be performed. In addition, a separate mask process for forming the tunnel oxide film 16 must be performed.

Therefore, there is a problem that the yield is reduced as the manufacturing cost of the semiconductor device increases.

Second, the area of the gate insulating film 15 of the cell transistor CT should be 10 times greater than that of the tunnel oxide film 16 due to the memory cell operation characteristics. Due to the increase in the area of the cell transistor CT, the overall memory cell area increases.

Third, by using F-N tunneling in data erasing and program operation, a high voltage (Vpp) of about 15V is required. In order to use the high voltage Vpp, the formation of the high voltage transistor is necessary to the peripheral circuit. Therefore, there is a problem that the overall manufacturing process of the memory cell is increased and the manufacturing process is complicated.

Fourth, there is a problem that the chip area as a whole increases as the transistor for high voltage is formed.

Fifth, in order to use F-N tunneling, since a predetermined electric field is required, scaling of a memory cell is difficult.

Accordingly, the present invention has been proposed to solve the above problems of the prior art, and has various objects as follows.

First, it is an object of the present invention to provide a nonvolatile memory cell that can reduce the manufacturing cost by simplifying the manufacturing process in manufacturing the nonvolatile memory cell.

Second, another object of the present invention is to provide a method of operating a nonvolatile memory cell that can solve various problems caused by using F-N tunneling to erase and program data of the nonvolatile memory cell.

Third, another object of the present invention is to provide a method of manufacturing the nonvolatile memory cell.

According to an aspect of the present invention, a word line, a bit line intersecting the word line, a program line extended in a direction parallel to the bit line to intersect the word line, and A first selection transistor connected to a point where a word line and the bit line intersect and selected by the word line, and a second selection selected by the word line connected to a point where the word line and the program line intersect Electrons are injected into the cell gate by a transistor connected between the transistor and the first select transistor and the select line and by a first bias transmitted through the first select transistor and a second bias applied through the select line during a program operation A first cell transistor, the second selection transistor, and the selection to perform a program operation A second electrode connected between the lines and injecting holes into the cell gate by the first bias transferred through the second select transistor and the second bias transferred through the select line in an erase operation to perform an erase operation A nonvolatile memory cell comprising a cell transistor is provided.

According to another aspect of the present invention, there is provided a method of operating a nonvolatile memory cell, wherein during an erase operation, a ground voltage is applied to the word line and the program line, and the selection line and Injecting a hole voltage into the cell gate by applying a power supply voltage to a substrate, and applying a power supply voltage to the word line and the selection line and applying a ground voltage to the bit line and the substrate during a program operation, An operation of a non-volatile memory cell to perform a read operation by applying a power supply voltage to the word line and a read voltage lower than the power supply voltage to the bit line, and applying a ground voltage to the selection line during a read operation. Provide a method.

According to still another aspect of the present invention, there is provided a semiconductor substrate of a first conductivity type defined by first and second regions, and a second conductivity type in the first region. Forming a well region of the well region, forming a select gate and a cell gate separated from each other in the first and second regions, respectively, and exposing the well region exposed between the select gate and the cell gate of the first region Forming a source / drain region of a first conductivity type in each, and forming a source / drain region of a second conductivity type in the substrate exposed between the selection gate and the cell gate of the second region; A method of manufacturing a nonvolatile memory cell is provided.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. do.

Example

4 is an equivalent circuit diagram of an EEPROM cell according to a preferred embodiment of the present invention, and FIG. 5 is a plan view of the EERPOM cell shown in FIG. 6A is a cross-sectional view taken along the line AA ′ of FIG. 5, FIG. 6B is a cross-sectional view taken along the line BB ′ of FIG. 5, and FIG. 6C is a cross-sectional view taken along line CC ′ of FIG. 5. It is a cross-sectional view shown. In addition, FIGS. 7A to 7D are cross-sectional views illustrating the manufacturing method of FIGS. 6A to 6C simultaneously. Here, the same reference numerals among the reference numerals shown in FIGS. 4, 5, 6A to 6C, and 7A to 7D are the same elements for performing the same function.

EEPROM Cell

An EEPROM cell according to an exemplary embodiment of the present invention will be described with reference to FIGS. 4, 5 and 6A to 6C.

As shown in FIGS. 4, 5, 6A, and 6C, an EEPROM cell according to a preferred embodiment of the present invention may include a first cell transistor CT ₁ and a second cell transistor CT ₂ storing data. And a first selection transistor ST ₁ connected between the first cell transistor CT ₁ and the bit line BL and selected by the word line WL, the second cell transistor CT ₂ , and a program line. A selection line connected between the PLs and selecting one of the second selection transistors ST ₂ selected by the word line WL and one of the first and second cell transistors CT ₁ and CT ₂ . SL). In this case, the first cell transistor CT ₁ and the first select transistor ST ₁ are NMOS transistors, and the second cell transistor CT ₁ and the second select transistor ST ₂ are PMOS transistors.

As illustrated in FIG. 6A, an N well 112 (N-Well) is formed in a predetermined region of the P-type semiconductor substrate 111 in the first cell transistor CT ₁ and the second cell transistor CT ₂ . In addition, a plurality of device isolation layers 113 are formed in a predetermined region of the substrate 111 on which the N well 112 is formed. On the substrate 111 where the N well 112 is not formed, a gate insulating layer 114 (hereinafter, referred to as a first gate insulating layer) of the first cell transistor CT ₁ is formed, and a substrate on which the N well 112 is formed ( A gate insulating layer 115 (hereinafter referred to as a second gate insulating layer) of the second cell transistor CT ₂ is formed on the 111. The cell gate electrode 116a having a predetermined width is formed along the stepped portion of the entire structure in which the device isolation layer 113, the first gate insulating layer 114, and the second gate insulating layer 115 are formed. In this case, the cell gate electrode 116a is used as the gate electrode of the first and second cell transistors CT ₁ and CT ₂ . In addition, first source / drain regions 117a and 117b are formed on the substrate 111 exposed to both sides of the cell gate electrode 116a as shown in FIG. 6B.

As a result, an NMOS type first cell transistor CT ₁ is formed on the semiconductor substrate 111 on which the N well 112 is not formed, and a PMOS type second cell transistor is formed on the semiconductor substrate 111 on which the N well 112 is formed. (CT ₂ ) is formed.

As shown in FIG. 6B, the first select transistor ST ₁ includes a first gate insulating layer 114 formed on the semiconductor substrate 111 and a first select transistor ST formed on the first gate insulating layer 114. ₁ ) a gate electrode 116b (hereinafter referred to as a first gate electrode) and a first source / drain region 117a / 117b formed in the semiconductor substrate 111 exposed to both sides of the first gate electrode 116b. Include. In this case, the first source / drain regions 117a and 117b are formed of high concentration N +. Therefore, the first selection transistor ST ₁ becomes an NMOS transistor.

As shown in FIG. 6C, the second select transistor ST ₂ is formed on the second gate insulating layer 115 formed on the semiconductor substrate 111 on which the N well 112 is formed, and on the second gate insulating layer 115. Second source / drain formed on the formed gate electrode 116c (hereinafter referred to as a second gate electrode) for the second selection transistor ST ₂ and the semiconductor substrate 111 exposed to both sides of the second gate electrode 116c. Regions 118a / 118b. In this case, the second source / drain regions 118a and 118b are formed of high concentration P +. Therefore, the second selection transistor ST ₂ becomes a PMOS transistor.

Meanwhile, '119' illustrated in FIG. 5 is a contact plug.

That is, since the EEPROM cell according to the preferred embodiment of the present invention forms a cell transistor without forming the N + buried layer and the tunnel oxide layer as in the above-mentioned conventional technology, an unnecessary mask process can be omitted. Therefore, the manufacturing process can be simplified and the manufacturing cost can be reduced. In addition, since the capacitance interposed between the control gate and the substrate does not separately form the gate insulating layer, the overall area of the memory cell can be reduced.

How EEPROM Cells Work

The EEPROM cell according to the preferred embodiment of the present invention proceeds in the following manner without performing an erase and program operation using F-N tunneling as in the conventional EEPROM cell mentioned above. That is, in the EEPROM cell according to the preferred embodiment of the present invention, as electrons or holes are injected into the cell gate electrode 116a, an erase or program operation is performed while the threshold voltage of the memory cell is changed. At this time, the difference of the current according to the change of the threshold voltage is sensed to read the data of the EEPR0M cell. Hereinafter, referring to Table 2, the read, erase and program operation characteristics of the EEPROM cell of the present invention will be described.

Operation mode Mechanism WL BL PL SL Board elimination Hole injection GND Floating GND V _CC V _CC program Electron injection V _CC GND Floating V _CC GND Reading - V _CC Vread Floating GND -

Read action

For the read operation of the EEPROM cell according to the preferred embodiment of the present invention, after turning on the first select transistor ST ₁ formed of the NMOS and applying the read voltage Vread to the bit line BL, the first cell The current flowing through the channel of the transistor CT ₁ is identified. At this time, when the threshold voltage of the cell gate electrode 116a exceeds OV, no current flows, and when the threshold voltage is 0V or less, current flows. In other words, when the threshold voltage of the cell gay electrode 116a exceeds OV, the cell gay electrode 116a is recognized as an erase state.

Erase operation

In the erase operation of the EEPROM cell according to the preferred embodiment of the present invention, the ground voltage GND is applied to the word line WL, the ground voltage GND is applied to the program line PL, and the selection line SL is applied to the selection line SL. _{Apply the} power supply voltage (V _CC ).

Accordingly, the first select transistor ST ₁ is turned off while the second select transistor ST ₂ is turned on. Therefore, the ground voltage GND applied to the program line PL is transferred to the drain region 118b of the second cell transistor CT ₂ , and the ground voltage GND is applied to the drain region 118b of the second cell transistor CT ₂ . (GND) is supplied. On the other hand, the power supply voltage V _CC is supplied to the source region 118a of the second cell transistor CT ₂ through the selection line SL.

In this way, the second cell transistor (CT ₂₎ a source region (118a) and a drain region (118b), the voltage drive because of the second cell transistor (CT _2), the hole number of the channel region (not shown) arises between that occurrence of do. In this case, when a power supply voltage V _CC is applied to the semiconductor substrate 111, a plurality of holes are injected into the cell gate 116a through the second gate insulating layer 115.

As a result, the cell gate 116a becomes positive, and the threshold voltage of the cell gate 116a exceeds 0V.

Program behavior

For a program operation of an EEPROM cell according to a preferred embodiment of the present invention, that is, to apply a threshold voltage of the cell gate 116a to OV or less, a power supply voltage V _CC is applied to the word line WL and a bit line ( The power supply voltage V _CC is applied to the selection line SL while the ground voltage GND is applied to BL.

Accordingly, the first select transistor ST ₁ is turned on while the second select transistor ST ₂ is turned off. Therefore, the ground voltage GND applied to the bit line BL is transferred to the drain region 117b of the first cell transistor CT ₁ , and the ground voltage GND is applied to the drain region 117b of the first cell transistor CT ₁ . (GND) is supplied. On the other hand, the power supply voltage V _CC is supplied to the source region 117a through the selection line SL.

In this manner, the first cell transistor (CT ₁₎ a source region (117a) and a drain region electrons generated number to a channel region (not shown) of the result voltage drive to a first cell transistor (CT ₁₎ occurs between (117b) of do. In this case, when the ground voltage GND is applied to the semiconductor substrate 111, a plurality of electrons are injected into the cell gate 116a through the first gate insulating layer 114.

As a result, the cell gate 116a is charged with electrons so that the threshold voltage of the cell gate 116a becomes 0V or less.

That is, according to the method of operating the EEPROM cell according to the preferred embodiment of the present invention, as described above, the erase and program operations of the memory cell are performed by injecting holes or electrons into the cell gate without using FN tunneling. do. Therefore, it is not necessary to use the high voltage required for F-N tunneling, so the formation of the high voltage transistor is unnecessary.

This can reduce the area increase due to the formation of the high voltage transistor, thereby reducing the area of the entire memory cell, and can reduce the overall process step since a separate process for forming the high voltage transistor is not required.

Manufacturing method of EEPROM cell

7A to 7D, a method of manufacturing an EEPROM cell according to a preferred embodiment of the present invention will be described. Here, the manufacturing method for forming the resultant of Figs. 6A to 6C are shown simultaneously for convenience of description.

FIG. 6A is a cross-sectional view taken along the line AA ′ of FIG. 5, in which first and second cell transistors of an NMOS and a PMOS are simultaneously formed. FIG. 6B is a cross-sectional view taken along the line BB ′ of FIG. 5, and a first selection transistor and a first cell transistor of the NMOS are formed. 6C is a cross-sectional view taken along the line CC ′ of FIG. 5, and a second selection transistor and a second cell transistor of the PMOS are formed.

Hereinafter, a region cut along the line A-A 'is referred to as a first region, a region cut along the line B-B' is referred to as a second region, and a region cut along the line C-C 'is referred to as a third region.

First, as shown in FIG. 7A, an impurity ion implantation process is performed to dope the semiconductor substrate 111 to P-type or N-type. Here, a P-type semiconductor substrate 111 doped with a P-type is provided.

Subsequently, a mask process and a well ion implantation process are performed to form a well region 112 in a portion of the semiconductor substrate 111 in the first region A-A ', and the semiconductor substrate in the third region C-C'. The well region 112 is formed in the 111. In this case, the well region 112 is formed of an N well.

That is, the first cell transistor CT ₁ of the PMOS is formed in the semiconductor substrate 111 of the first region A-A 'in which the well region 112 is formed, and the first region in which the well region 112 is not formed. The NMOS second cell transistor CT ₂ is formed in the semiconductor substrate 111 in the region A-A '.

Subsequently, as shown in FIG. 7B, a plurality of device isolation layers 113 are formed in the first to third regions A-A ', B-B', and C-C ', respectively. In this case, the device isolation layer 113 may be formed through a LOCOS (LOCal Oxidation of Silicon) process or a shallow trench isolation (STI) process.

Subsequently, as illustrated in FIG. 7C, the first gate insulating layer 114 is formed on the semiconductor substrate 111 of the first to third regions A-A ', BB', and C-C 'by performing an oxidation process. ) And the second gate insulating film 115 are formed.

That is, the first gate insulating layer 114 is formed on the semiconductor substrate 111 of the first region A-A 'where the well region 112 is not formed, whereas the first region (not shown) is formed. The second gate insulating layer 115 is formed on the semiconductor substrate 111 of A-A '.

The first gate insulating layer 114 is formed on the semiconductor substrate 111 of the second region B-B ', and the second gate insulating layer 115 is formed on the semiconductor substrate 111 of the third region C-C'. ).

Subsequently, conduction is performed along the steps of the entire structure in which the first gate insulating layer 114 and the second gate insulating layer 115 in each of the first to third regions A-A ', BB', and C-C 'are formed. Layer 116 is deposited. In this case, the conductive layer 116 is formed by depositing a polysilicon film in a single layer or by stacking tungsten (W) or tungsten silicide layer (WSi ₂ ) on the polysilicon film.

Subsequently, as illustrated in FIG. 7D, a mask process and an etching process may be performed to perform the cell gates 116a and the first gate in each of the first to third regions A-A ', BB', and C-C '. The electrode 116b and the second gate electrode 116c are formed.

For example, the cell gate 116a is formed in the first region A-A ', and the cell gate 116a and the first gate electrode 116b are simultaneously formed in the second region B-B'. In addition, the cell gate 116a and the second gate electrode 116c are simultaneously formed in the third region C-C '. In this case, the first and second gate electrodes 116b and 116c function as a word line WL.

Subsequently, a source / drain ion implantation process is performed on the resultant cell gate 116a and the gate electrode 116b formed thereon, thereby forming the cell gate 116a and the first gate electrode 116b of the second region B-B '. Source / drain regions 117a and 117b are formed in the semiconductor substrate 111 exposed to both sides.

In addition, source / drain regions 118a and 118b are formed in the well region 112 exposed to both sides of the cell gate 116a and the second gate electrode 116c of the third region C-C ′.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the present invention, since the process for forming the N + buried layer and the tunnel oxide film is unnecessary as in the aforementioned prior art during the manufacturing process of the nonvolatile memory cell, an unnecessary mask process can be skipped. have. Therefore, the manufacturing process can be simplified and the manufacturing cost can be reduced.

In addition, according to the present invention, the gate insulating film of the cell transistor having a large capacitance is not formed separately, so that the overall area of the memory cell can be reduced. Therefore, the design of the memory cell area is easy.

In addition, according to the present invention, in the operation of the nonvolatile memory cell, as described in the related art, holes or electrons are injected into the cell gate without using F-N tunneling to perform erase and program operations of the memory cell. As a result, it is not necessary to use a high voltage, and thus it is not necessary to form a high voltage transistor. This reduces the area of the memory cell as a whole by preventing the increase of the area due to the formation of the high voltage transistor, and reduces the overall process step since the separate process for forming the high voltage transistor is unnecessary.

Therefore, the nonvolatile memory cell according to the present invention can be easily used for nonvolatile memory cells using a single power supply.

Claims (15)

Wordline; A bit line intersecting the word line; A program line extended in a direction parallel to the bit line to intersect the word line; A first selection transistor connected to a point where the word line and the bit line cross each other and selected by the word line; A second selection transistor connected to a point where the word line and the program line cross each other and selected by the word line; A first cell gate, connected between the first select transistor and the select line, the first cell gate being connected by the first bias transmitted through the first select transistor and a second bias applied through the select line in a program operation; A first cell transistor in which electrons are injected into the first cell gate to perform a program operation; And A second cell gate, connected between the second select transistor and the select line, to a first bias transferred through the second select transistor and a second bias transferred through the select line in an erase operation; A second cell transistor in which holes are injected into the second cell gate to perform an erase operation; Non-volatile memory cell comprising a. The method of claim 1, And the first cell gate and the second cell gate are connected to each other. The method of claim 1, And the first and second cell transistors are transistors of different types. The method of claim 3, wherein And the first cell transistor is an NMOS transistor, and the second cell transistor is a PMOS transistor. The method of claim 1, And the first and second selection transistors are formed of transistors of different types. The method of claim 5, And the first select transistor is an NMOS transistor, and the second select transistor is a PMOS transistor. The method of claim 1, And the first cell gate, the second cell gate, and the word line are formed of a single polysilicon layer. The method of claim 1, And the bit line and the program line are doped with different impurity ions. The method of claim 1, And the first cell gate and the second cell gate are in a floating state during the program and erase operations. A method of operating a nonvolatile memory cell according to any one of claims 1 to 9, In the erase operation, a ground voltage is applied to the word line and the program line and a power supply voltage is applied to the selection line and the substrate to inject holes into the second cell gate. In the program operation, a source voltage is applied to the word line and the selection line and a ground voltage is applied to the bit line and the substrate to inject electrons into the first cell gate. In a read operation, a read operation is performed by applying a power supply voltage to the word line and a read voltage lower than the power supply voltage to the bit line, and applying a ground voltage to the selection line. A method of operating a nonvolatile memory cell. 11. The method of claim 10, And the bit line is maintained in a floating state during the erase operation. 11. The method of claim 10, And the program line is maintained in a floating state during the program and read operations. Providing a first conductivity type semiconductor substrate defined by first and second regions; Forming a well region of a second conductivity type in the first region; Forming a cell gate in each of the first and second regions, and forming a select gate separate from the cell gate in each of the first and second regions; Forming a source / drain region of a first conductivity type in the well region exposed between the selection gate and the cell gate of the first region; And Forming a source / drain region of a second conductivity type in the substrate exposed between the selection gate and the cell gate in the second region; Method of manufacturing a nonvolatile memory cell comprising a. The method of claim 13, And the cell gates formed in the first and second regions are connected to each other. The method of claim 13, And the select gates formed in the first and second regions are connected to each other.

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